Engagement Diamond FAQ

(1 August 95 version, 1651 lines)
by Peter Mlynek, mlynek@chem.wisc.edu


Diamonds have been considered an important item in an engagement ring. This post should provide you with information about diamonds (the 4 C's), where to shop for diamonds, what the approximate prices are, and most importantly some straight talk that you wont hear from people selling these stones. Although this post is aimed at couples looking at buying engagement rings, it could also be useful for people wanting to know about diamonds in general.

Table of Contents

  1. About this F. A. Q.
  2. Straight Talk About Diamonds
  3. From a Mine to Your Finger
  4. Buying Diamonds
  5. Value/Quality of Diamonds
  6. Carat
  7. Color
  8. Clarity
  9. Cut
  10. Prices

  1. About this FAQ
  2. 1(a) Technical Details of this F.A.Q. Posting

    I'll try to post this every so often on the soc.couples.wedding and alt.wedding groups. Every time I post this, I spend several hours updating and rewriting parts of it. It is still not finished, and there are still some important things that I'd like to include in this F.A.Q., but do not for lack of time on my part.

    It is important to realize that I am NOT in the diamond business. I am just a person who has gone through the ordeal of buying a nice diamond engagement ring for my girlfriend. Hence I am not an expert. Most of what I write I believe is correct, but it is likely that make some mistakes, so feel to comment on it directly to me, or to others on the net. I'll take your corrections and incorporate them into the next post.

    Furthermore, on some issues we might not agree; some things are really a matter of personal opinion, so take what I write with a grain of salt. Don't sue me if I've lead you astray (well, I guess you can recover all the money that you've paid me to write this :-) ).

    Please use a constant spacing font; there is a small ASCII drawing of a diamond and a price tables later on.

    Also, please note that I am not yet really finished with this. The issues that I'd like to address in the updated version of this document are: what to look for in rubies, sapphires, etc.; the SI3 grade; newer price list; gold, settings, customs; fakes; treatment; more on color; more on different cuts of diamonds; DeBeers marketing campaigns, slogans; appraisals; certification; etc. These issues, along with enhancement of what I've written so far should about double the length of this FAQ :-(

    1(b) Use and Copying of this F. A. Q.

    If you are a person looking for information on diamonds as a consumer, please feel free to take this FAQ in parts or as a whole and do with it what you will. Feel free to print it out, give it to your friends, send it electronically, etc. Please leave my name (Peter Mlynek, mlynek@chem.wisc.edu) attached to it, if you can. If you add these files onto your Web page, please let me know of the location, since sometimes I get requests about that.

    If you are a professional in the jewelry business, please do not copy these files for any reason. Though I am a pretty reasonable fellow, I've devoted way too much time to this so that someone else can make money off my work, but more importantly, I wouldn't want to be held liable if information in this F. A. Q. is misused. Feel free to e-mail me, and we can talk about business use of this F.A.Q.; some firms already have my permission to use it.

    1(c) Why I Do This

    About two years ago, when I was in the market for an engagement ring, I was not able to find any information about engagement rings, and diamonds in particular. The only apparent source of information was the sales folks in jewelry stores. Although most of these people are trustworthy, it is hard to separate the salestalk from facts. Especially when it comes to stuff that you are told that you need to get, but spending loads of money on half an ounce of minerals and metal, does not make good sense.

    There really is not much information when it comes to jewelry. When I buy a car, I look through Car and Driver or a similar magazine, people who buy stereo component read up on them in an audiophile magazines, for real estate I reach for MLS, for photo gear I look through Popular Photography, for toaster I check out Consumer Reports. For diamonds...nothing! Anything that you do find are just advertisements. This is strange, considering that jewelers expect engaged couples to shell out loads of money for something that most folks are in the dark about. A consumer guide for diamond buyers is hence much more needed than for other items.

    BTW, please do not ask me to recommend a jeweler, or a diamond dealer. Though I know several good ones, my recommendations would be colored too much by my personal taste (which is undoubtedly different from yours), and my experience is too anecdotal.

    1(d) Learning More About Diamonds

    To learn more about diamonds, and jewelry in general, hit your local library. Larger public libraries should have lots of info on geology, minerals, etc. (real useful huh, ;( ), but they may also have trade periodicals. There are a number of trade publications on jewelry, precious stones, diamonds, etc.

    You can also hit the book stores; there are a number of up to date books that might be useful. You really should check out books beyond the 3 page section on engagement rings in wedding guides.

    And most importantly, go to a large number of stores, talk to store owners. Do talk to the store owners, managers, the big cheeses. Find out their names before walking in and ask for them by name when you visit their store. The average salesperson is hopelessly and blissfully ignorant of anything beyond the pedestrian knowledge of precious stones (yes, I know, there are exceptions); after all, they are there to _sell_ the diamonds, and not to know about them. AND look at several dozen stones, even those that you are not interested, so that you understand the differences between the them.

    And most importantly, don't think that by reading this FAQ (or even by writing one) you will become any type of an expert on diamonds.

    1(e) Your Help is Needed

    There are several things you, as a consumer, can do to help me. First of all, if you find a mistake, an error, or an omission, please get in touch with me. I really don't want to lead people astray in this terribly confusing business.

    Second, it would be too expensive for me to get the up to date prices on regular basis. If you've found my F. A. Q. helpful, please copy the price table in the price section, update it and send it to me. After all, I've spend dozens of hours on this...can you spare a few bucks, and a couple of minutes helping me and others?

    Third, I am finishing my thesis and looking for a permanent position. If you know of a small to medium firm that could you a person with a PhD in inorganic chemistry (minor in analytical chem), and with an MBA in finance (some operations research), please send me a note; I'd be eternally grateful. :-)

  3. Straight Talk about Diamonds
  4. 2(a) Think About the Purchase Logically!

    First things first. Get this through your head:

    You Don't Need An Engagement Diamond!

    You don't need any diamonds. A diamond is a luxury. You need clothing, shelter, food, love,... . You don't need a diamond. You may want it, but you don't need it. Owning a diamond is, I'd say, up around the 4th level of Mazlow's pyramid model of Theory of Needs, not on the 2nd as most jewelers would lead you to believe. Diamond is not an indication of love. The only thing you sorta need is an engagement and a wedding ring, to show others that the man/woman is no longer available; but there is no rule that says that the rings need to contain any diamonds.

    And of course, there is no correlation between the cost of the diamond, and how much a couple loves each other, or how good the marriage will be.

    And as a luxury good, diamonds really suck. Consider other luxury goods: fur coats, luxury cars, fancy TVs, etc. Well, you need clothing, so as long you need a coat to keep warm during the cold winters, why not buy an expensive fur coat. As long as you want to spend time watching the tube, why not on a large 52-inch Sony. As long as you need to drive from one place to another, why not in an S-series Mercedes. But diamond in your ring just sits there. Its only purpose is to be esthetically pleasing. But as you know, beauty is in the eye of the beholder....

    Diamond also sucks as a luxury good from another angle. A lot of luxury goods are sold so that others might admire them, and thus reflecting well on their owners (consciously or not!). But with diamonds others have no idea. First of all, there are tremendous value differences between diamonds that look alike. Second of all, no one can tell the difference between a real diamond and a fake just by casual observation. And third of all, very few people can tell the difference between a good diamond and a poor one, even if you tell them the specifications thereof. Hence the satisfaction of owning a diamond comes from the warm feeling of you knowing that it is a real and good diamond, and not from wanting to be admired or to keep up with the Joneses'. You are buying the diamond for your happiness, not what anyone else thinks.
    Bottom line: don't buy a diamond to impress others; buy it to satisfy yourself/your fiancee.

    So, look for a diamond only when you really want it and realize that you are basically splurging on yourself/your fiancee.

    And buy a diamond that you are happy with and that you will be happy with for the rest of your life. This is extremely important!! Decide what diamond you want, what you are going to be happy with, and then find such a diamond. Realize that you/your wife will be looking at that diamond for rest of the life (If you don't think it will be for rest of your/her life, you have bigger problems than what engagement ring to buy!).

    Do not buy the _almost_ right diamond. If you do that, 5, 10 or 30 yrs down the road, you'll regret that you've wanted to save yourself a few hundred dollars instead of getting what you want. And there will be nothing you could do; substituting a better diamond for the one originally offered to the woman is sacrilegious. You can buy an _almost_ perfect car, or a computer, because in 7 yrs or so you'll just buy a another one, but baby, this particular diamond is very special. (If you are buying diamonds for earrings, bracelet, etc., buying the almost perfect diamonds is no big deal, you can always upgrade or buy a whole new piece later.)

    It is necessary to approach the engagement buying experience from a rational viewpoint. Leave your emotions at home. Think with your head, not with your heart. Think with your head, not with your loins. Don't let hormones guide your buying decisions. I realize that this is very difficult for people in love, and with the excitement of getting married, and all, but do not make this an emotional purchase. Don't fall for any 'mystique' of diamonds, or 'isn't this pretty' arguments from your jeweler. The purchase needs to be approached with the same attitude (if not more serious) as hiring the band or a caterer for the wedding (except this diamond will be around long after the guests recall how wonderful the cake tasted or the music sounded).

    If you are offended by this section, I apologize. I certainly don't wish to patronize anybody, it's just that some people think that a diamond is needed for an engagement, and need to be whacked on the head to realize that this is not so, hence the strong language. :-)

    2(b) Gem Alternatives to a Diamond

    Alternatives to diamonds are numerous: if you like a certain color, buy a precious stone in that color. There are suitable stones for any color you would ever want. Is there a color that holds a special meaning to you as a couple?

    If you/your wife are going to be wearing a ring with a gemstone everyday, like is the tradition with engagement and wedding rings, make sure that the stones are both tough and hard enough to handle the hundreds of thousands of hours of wear. Yes, you can get an emerald or an opal, but you really need to be careful...can you maintain the vigilance for the next 50-odd years day in and day out?

    There really is only one gemstone that is tough and hard enough for everyday wear: corundum (aluminum oxide). If corundum is red, it is named a ruby, and if it is blue or any other color besides red, it is called a sapphire.

    2(c) Alternatives to a Diamond Engagement Ring

    Another approach you might consider instead of one large stone, is lots of small precious stones in the engagement ring. They can be diamonds, but you can use colored stones as well. You can even design it yourself in any shape/style you want, if a jeweler doesn't carry it, or can't get it. A lots of small diamonds will also be much cheaper then one large one.

    Another option is to be minimalist. If the fiancee is a practical person, a gaudy ring might not be the way to go. A simple gold band might not be too obtrusive, and not get in the way. When skin diving, kneading dough, performing surgery, fixing copying machine, shooting hoops, wearing thin gloves, etc., a ring with a diamond, precious stones, or actually anything protruding, such as prongs, will need to be removed for the fear of damage either to or by the ring, stones. A simple gold band also wont portray you as a rich person (falsely or not), in public, and wont draw attention to itself in the wrong neighborhood. And again you do have many options. Sure, it could be a simple gold band, but it also can be gold band with a special design that is meaningful to you as a couple. It could be gold of various colors as well. Actually, it does not even have to be gold; consider silver, platinum, palladium,...

  5. From a Mine to Your Finger
  6. (I've been told that this section is pretty much the most boring of all sections of this FAQ, but it may give you some helpful info on how this business operates, hence I've kept it here)

    The process of getting finished diamonds is seemingly a simple one: mine -> DeBeers -> cutter -> dealers -> retailer -> groom -> bride

    3(a) Mines

    By pure chance, most diamond deposits have traditionally been located in environmentally and/or politically challenging regions of Earth. Majority of diamonds have been mined in Republic of South Africa, other sub-Saharan countries, and Siberia. There are also smaller diamond deposits in other parts of the world like northern South America, Arkansas, etc. Recently, a large deposit of brown diamonds have been found in Australia. Within a last year or two, millions of acres between the Great Slave Lake and the Arctic Ocean in Canada's NWT have been claimed by companies prospecting for diamonds (so far the news is not too optimistic).

    3(b) DeBeers

    DeBeers is an international company that buys rough diamonds directly from the diamond mine owners, and then resell them to the cutters or institutional investors. Maintaining a worldwide monopoly and monopsony is has been very profitable for DeBeers, however, it also has been very expensive for them. DeBeers expense comes not only from the traditional monopoly/monopsony expense of having to satisfy both the vendors and the clients to avoid disintermediation, but also in risk costs such as large capitalization. DeBeers does take a very long term view of this business: we are talking horizons of decades, not of the next fiscal quarter. Overall, it is a very successful business.

    Although DeBeers has been traditionally headquartered in RSA, due to potential civil unrest (or a civil war) towards the end of the Apartheid RSA, they've moved to London; the reason given by the firm was to give the company a more international location, a more central location.

    DeBeers is extremely good in securing the rough; they've written contracts with right wing dictatorships, Marxist- Leninist African dictators, USSR (who at the same time was trying to overthrow RSA and destroy capitalism, including DeBeers), democratic governments, private enterprises, etc. Because they are a monopoly, they are not permitted to operate in the US due to the anti-trust legislation, so for most of the century they have been represented in the US by Ayer's, a marketing firm.

    3(c) Cutters

    Cutting firms from all over the world buy rough diamonds from DeBeers in sessions called the "sights" several times a year. These are by invitations only, and besides cutters also other large institutional investors are brought in. A representative of a buyer along with his expert is brought a box full of diamonds; then they have some time to look it over and decide whether to purchase or not. The price is set, no negotiating, no substituting allowed, no partial sales, no nothing. And if the buyers fail to buy what's offered, they are in danger of not being invited back in the future.

    Cutting of diamonds is done all over the world. Traditionally it has been done in Antwerp, but with low cost of labor elsewhere, other cutting businesses have sprung up. A large portion of diamonds is cut in India; usually the very small stones are cut there, 10 points or less. United States also has a cutting industry, but it is limited only to the largest roughs, 3-4 carats min, due to large labor costs. The best cut diamonds have traditionally come from USSR; the workers there were taught what is the proper cut, and the diamonds were cut precisely to those dimensions, regardless of how much rough diamond they had to waste. On the other hand, diamonds that have been cut in Israel are cut to bring in the most money; and since diamonds are sold by weight, their cutters try to cut off the least amount of the rough that they can get away with and still make a decent diamond.

    3(d) Diamond Dealers

    Diamond dealers from all over the world then buy these cut stones from the cutters. One of the largest communities of diamond dealers is found on 47th Street in New York. Most of the businesses are family owned, and family run for generations (the idea is that if an employee rips you off, at least it stays in the family :-) ). The ethics standards are extremely high; hundreds of thousands of dollars are exchanged with a handshake, and even the smallest infractions may make a dealer a persona non-grata for life. Other metropolitan areas have similar concentrations of diamond dealers, usually called "the diamond district" or "the diamond house", etc.

    3(e) Retailers

    Jewelers from the rest of the country then buys the diamonds from these dealers, and then sell it to the public. There are several ways of doing this: for most pieces, the jeweler puts in an order of a variety of gems from various wholesalers, including diamonds, from one or several diamond dealers. Usually a jeweler works with several diamond dealers, not only to shop around for the best price, but some dealers specialize in certain types of diamonds. But, since diamonds are expensive to keep in inventory, and if you are looking for a stone in certain grade, it is likely that the retailer will probably not have it. In this case the jeweler can order it on a memo. This service does not cost you anything, and does not oblige you to buy the stone, but does oblige you to visit the store again when the parcel of several diamonds similar to what you've requested arrives, and consider buying one.

  7. Buying Diamonds
  8. 4(a) Retailer Options

    By retailers I mean jewelers that deal with the end customer. Most people interested in buying jewelry use this venue, and these businesses are set up to serve them. There are big differences between jewelers, each of which has some sort of an advantage over another. Which type of a jeweler is right for you depends.... Though it is hard to categorize, and generalize, since there are always exceptions, please take these descriptions with a grain of salt. In any case, let me try to describe the different type of jewelers:

    Mall jewelry stores located in large shopping centers are great for buying jewelry for Christmas presents, Bday presents, spur of the moment purchases, etc. The mall jewelry store lives off the large volume of average shoppers who stream by the storefront. Hundreds of shoppers a day stop by, most of whom do not know much about jewelry, and this reflects on the sales personnel. The salespersons behind the counter are probably the most uninformed people in the business...they may be selling toasters one year, jewelry the next. They may know how to sell by their knowledge about diamonds may be pretty negligible. There also is another problem that a buyer should be aware of when shopping for a diamond: since most people who shop for diamonds shop around, and the mall jewelers realize this, they in a dilemma-- it is difficult to compete on price, since the mall jewelers overhead is very high compared to other jewelry shops. If a mall jeweler wants to capture this market, the store either has to give more to the customer (e.g. better service, financing, credit, etc.) or sell cheaper (i.e. poorer quality) goods. Diamond shoppers will try to compare the goods from one store to the next, usually writing down the price, and the characteristics of the stone, specifically the weight, color, and clarity. Unfortunately for the buyer, there is no easy scalar value of cut, and since it is the most difficult of the 4 C's to understand, the mall jeweler may buy poorly cut, cheaper stones, in order to compete with the other jewelers. Overall, though there are great reasons to shop the mall jeweler, and there are wonderful products you may purchase there, when shopping for an expensive item such as an engagement diamond, I wouldn't put the mall jeweler at the top of my list.

    A downtown jewelry store is another option for a diamond buyer. This type of a store is located on a busy street that has a sizable pedestrian traffic, usually around the center of a city. The sales here are not as frequent as in a mall store, but the sales are usually bigger. The staff is usually more knowledgeable, and the store may have a long history and a good reputation. Since most of these stores have a workshop, it should not be a problem to get a custom made or a unique engagement ring. People who patronize these establishments are usually looking for high levels of service and quality. The prices may likewise be high as well. However, if the store is locally owned, negotiating a better price is a possibility.

    Strip mall jewelers probably offer the best of the two options describe above. (Strip malls are a dozen shops with a parking lot in front of them, united by some sort of a covered sidewalk and some color/design scheme; strip malls are found in every suburban community in America) Some strip mall jewelers may be a family business, others a part of a national chain. Some stores may have a workshop. Usually reasonable prices for reasonable products, and most items are very negotiable.

    Another option is discount superstores like Wal-Mart. Though it may seem less then tactful to most people to propose with a ring bought along with a toothpaste and a pair of sneakers, if you are a practical person and just want a small, low priced diamond, this might be your option. Look into these superstores if you want an engagement ring that costs less than $1000.

    4(b) Wholesalers/Dealers

    The diamond dealers and jewelry wholesalers are usually found in an area of downtown of larger cities, either in a single building or in a several block area, termed something like "the jewelry center" or "the diamond district" etc. Though their customers are usually retail jewelers, they do sometimes deal with the end user. There is only one reason to deal with the wholesaler: best prices.

    If you want to deal with a wholesaler, you should know your stuff. Do not expect the wholesaler to spend time explaining to you what the 4 C's are. Usually, you just call the dealer up, tell them what diamond you wish to purchase, set up an appointment well in advance so that they can obtain several stones close to what you want. You certainly can just go into the store without an appointment, but it is unlikely that they'll just happen to have the stone that you are looking for.

    Expect the dealing to be professional, unemotional, none of the 'diamond is for ever', 'diamonds signify love', etc. stuff. You will not be able to get the real wholesale price, more likely you'll just split the difference between the wholesale price and the retail price. Be prepared to negotiate, but of course, you need to be knowledgeable about the prices, so you can support you bargaining position.

    Also, no checks excepted. Credit cards excepted rarely, and only if you are willing to pay for the bank charge, which of course you can negotiate as well. Overall, dealing in cash is the best; hundred dollar bills welcome.

    4(c) Private Parties

    Just like it is possible to get a good value on a used car through the ads in the paper, so it is possible to buy a diamond. The people who advertise in papers usually are trying to sell gems that were inherited, or people who go to estate sales and who picked up some gems cheaply. Also, some diamond dealers advertise in large city newspapers.

    Of course, one needs to be very careful when buying through the private parties. Are you willing to give a stranger a large sum of money for a piece of a sparkling rock that may turn out to be a fake, or misrepresented? Caveat Emptor.

    4(d) What Sales Talk to be Prepared For

    In order for the retailer to get money out of you for a piece of jewelry, like in any other field of selling, there are many different strategies to do this. The ones listed below are gathered from back issues of Jeweler's Circular Keystone (a trade magazine for the jewelry retail industry) most of which should sound quite familiar from other sales folks such as a car dealers, or a real estate agents.

    Closings [JCK Feb 89, with my comments]

    When the Customer Indicates Willingness to Buy:

  9. Value/Quality of Diamonds
  10. 5(a) Overview of the Four C's

    Value of diamonds is determined by four input variables commonly referred to as "The four C's", which is the first thing that a sales clerk will tell you. The price of diamonds are driven by this value, as well as market forces (supply and demand). More on price later, let me concentrate on the four C's.

    These four C's are: cut (the styling of the diamond as well as the workmanship), clarity (the number/size/types of faults inherent of the diamond), color (how much off-white the diamond is), and carat (how much it weighs). You must know ALL of these in order to determine the value of each stone. Asking "is $4000 for 1 carat stone right?" is akin to asking "is $100,000 for 3 bedroom house right?"; for a house you must consider location, area of property, age, and dozen other things. $4000 might be ten times too expensive, or ten times too cheap.

    I've listed the 4 C's in section 5 through 9. They are in order of ease of understanding, not by importance.

    5(b) How Important Are These 4 C's to You

    So the value of diamonds is determined by the 4 C's:

    Value = F(cut, clarity, color, carats)

    Obviously you want to get the best of all of the 4 C's, but getting a diamond with the best clarity, best color, and best cut is a great way to rocket yourself into a poorhouse. Most folks would put the 4 C's in this order: carats (long pause), color, cut, clarity. My list is: the cut first, then color, weight and finally clarity. But this is personal preference. There is no right or wrong way of doing this. But let's see if I can come up with a recommendation of weighing the 4 C's against each other.

    This is my recommendation on deciding which diamond is this: decide which lowest grade of color you would except in your diamond. Also decide which lowest grade of clarity you cold live with. Yes, I realize that you want the highest grades possible, but now just consider the lowest grades. OK, it is likely that you would buy a diamond of these grades, but you would also probably consider buying a diamond 2, 3, or even 4 grades better in either clarity or color, but not much higher than that, since you'd be wasting money on better color and clarity, which you could be devoting in getting a better cut or carat weight. Now consider how important the cut is to you. The cut is not graded, (and is the most difficult of the 4 C's to judge), because the cut is a personal preference. Maybe you will like a stones that are less expensive better than those that the experts say are well-cut stones. Decide on the shape, range of proportions, finish, symmetry, etc. that you would accept (this is the most difficult step of your decision). Now, decide on how much money you'd like to devote to this diamond. Again, make it a range, not a single number. Now having those 3 C, as well, as the range of your budget, look for the biggest diamond, i.e. diamond of the greatest carats, that you've budgeted for (i.e. maximize value of the diamond only wrt carats).

    Now armed with the knowledge of what range of each of the 4 C's you are looking for, you'll be able to ask the jeweler for them. Since diamonds are not manufactured but mined and cut, tell the jeweler a range of what you'll except, not the specific grades. Then, when later the jeweler shows you several diamonds, then you'll have to juggle the 4 Cs along with the cost. Then it's going to be: well, diamond A is really nicely cut, but diamond B has a slightly better but a lot worse clarity, and diamond C has the best clarity and color of all but is much smaller then the rest, and diamond D is larger and has a great clarity but costs more then others, but on the other hand the diamonds E, F, G, from another jeweler have... ad infinitum. Basically, you'll have to try tweaking your choices within the parameters you've established, until you find and buy the diamond that you are happy with.

    But you can weigh the 4 C's along with your budget in any way you want... The above is only a suggestion. Most importantly, though, be sure to get a stone that you are absolutely happy with.

  11. Carat
  12. Carat weight refers to the weight of the diamond, not the size. By definition 1 carat is exactly 200 milligrams, although in past centuries this has varied. Since carats are measured by a balance, not a ruler, a diamond with 6 mm diameter (all precious stones are measured in mm, not in inches; nobody outside of the US uses inches) will weigh 8 times more then a 3 mm stone of similar cut (8 comes from 2^3).

    Note the spelling of carat. Don't confuse this with karat, which is a unit of purity of gold. 1 karat is 1/24th gold, hence 14kt gold is 14/24 pure. Purity of gold for jewelry varies from 9kt to 18kt, depending on the style, usage and country standards.

    Also, since other precious stones are measured in carats, and the density between the minerals varies, a 1 carat diamond will look a different size then a 1 carat topaz.

    Since most cut diamonds weigh less then a carat, and merchants would not be too found of saying, 'isn't this a nice diamond weighing a fraction of a carat,' the carat is subdivided into points. There are 100 point in a carat, just like there are 100 cents in a dollar. However, on your appraisal, receipt, and any other documentation, the weight will be specified in carats, and not points, as required by the Federal Trade Commission.

    Most diamonds sold are under 50 points, which go into tennis bracelets, pendants, earrings, side stones, etc. Diamonds reserved for engagement rings are usually of higher weight. Engagement diamonds go any where from 25 points to over a carat, with the average at 64 points (as of 92, dropping a point or two per year).

    One thing to note: please do not buy a diamond based only on its size. Selecting a diamond based on its size is akin to buying a house solely based on its square footage, a computer solely on its hard drive capacity, or a car on the engine size. Or, to put it in another way: "Selecting a diamond based on its size is the same as selecting a man on his" Yes, the carat weight is important, but it is just one of many other variables.

    Unfortunately, if you looking for a higher weighed stone, the value of diamonds increases with weight. Not only does the price increase for a higher carat diamond, but the price/carat increases as well. Not only that, but this increase increases (i.e. positive d^2 $ / d ct^2) Yes, this is on top of the cube root relationship between the diameter and the weight. Usually prices of diamonds are quoted in $/ct, not in $, so if you want to speak as an insider, do so as well (not that it is a good idea though).

    Since most potential grooms walk into a store with a round number in his head of how big a diamond he wants to purchase (50 points, 75 points, 1 carat), the merchant will sell him what he wants, and charge him accordingly. If he leans towards a slightly small stone, the argument presented is "well, you don't want the wife telling her friends that it is _almost_ a carat, do you?". Hence the price rapidly increases above these round figures, especially for the 1 carat hurdle, or another way of looking at it is that the increase of $/ct is slowed just before (or 5-10 points before) each round weight (i.e. negative d^3 $ / d ct^3 ?) If you can live with this _almost_ effect, then this is a good place to find _relatively_ cheaper prices, than a continuous $ vs ct.wt. graph would suggest.

  13. Color
  14. [note: sections 7(a) through 7(c) are most helpful; 7(d) - 7(g) are more background material that you'll find not really relevant but might be of interest]

    7(a) Introduction to Color

    Color of diamonds refers to how much yellow shows up in the diamond. The less yellow there is, higher the value. The most valuable diamonds are totally clear. Actually, there are diamonds that have various colors (such as brown, red, blue, green, etc.), and I have described them in section (g), but for when one says "color" when dealing with diamonds they are referring to how clear to yellow the diamond is.

    7(b) The G.I.A. Color Scale

    The most common grading system that you'll run across when shopping for diamonds is the one used by the Gemological Institute of America (GIA), which grades the color from D alphabetically to Z. D is totally colorless, and Z is slightly yellow. There are more yellowish diamonds available which look really nice in cocktail rings, but are usually considered inappropriate for engagement rings.

           Grade        Description
            D          \
            E           \      Traces of color, if present
            F           /     as visible only to the trained eye
            G          /
            H          \  
            I           \   "Near colorless": slight traces of color wont
            J           /   be apparent in mounted stones to other then a
            K          /           trained eye
            L          \
            M           \
            N            \       Diamonds show increasing yellow color
            O            /       even to an untrained eye
            P           /
            Q          /
            R          \          Stones appear yellow
           S-Z         /          even to untrained eye
    The GIA considers the D, E, and F to be colorless, G to J is "near colorless", K - M faint yellow, M - R very light yellow, and S - Z light yellow. However, this D to Z scale is continuous, and what they consider "very light yellow" may mean different thing that you'd call it. Unfortunately, I don't know of anyone who would put a numerical value on each grade; I've talked to dozens of jewelers, but nobody can associate an absorption coefficient with a particular grade. Besides the traditional method of judging color of stones (see below), there are colorimeters that a jeweler can buy, which will determine the grade within a 1/3 of a grade.

    7(c) Judging Color of a Diamond

    There are several associations/organizations/institutes that have various scales of measuring the color of diamonds, but the way that each of them grade the stones is by comparing the stone in question to a standard set of stones. Your jeweler may have a similar standards, which is very expensive, of course. To save money, some jewelers use artificial standards, which is OK for most purposes, but sometimes the material from which they are made is effected by UV light over periods of years, and may shift the grades slightly. And, it is also important that the size of the graded diamond is similar to the standards.

    When buying a diamond, it is important to see it unmounted, especially for the reason of judging the color. Since diamonds are designed to reflect all ambient light in all sorts of colors of the rainbow, you can not just look at it from the top. There are two ways of looking at a diamond, either by placing it on a level surface, or by putting it into a small plastic trough. On a level surface, make that _white_ level surface, place the diamond with table down, and look at it from the pavilion to the table; or from one side of the pavilion to the other side, i. e. in the girdle plane; or place the diamond with pavilion onto the surface, and with the culet pointing towards you, look through the girdle plane. If the jeweler doesn't provide a grading trough, just use a business card or a 3x5 card folded four time length-wise like a harmonica and make a dove-tail on the ends so that the diamond does roll off. Again, look at the diamond from the three angles described previously.

    It is very difficult to judge the color; you need to see two stones of adjacent color grades right next to each other in order to notice the difference with some difficulty. When showing it casually to your friends, the diamond will seem yellowish at about the K or L or lower grade. Although the apparent color of diamond depends on the setting, your complexion, etc., if you want your diamond to looks, don't buy a stone much bellow J. The average color for engagement rings in the US today is G to H. As far as the price goes, each grade is about 7 to 15% more expensive than the lower color grade, everything else being held the same.

    7(d) Diamond Color Data

    Unit sales of all diamonds by color (JKC June 1991)
        GIA color      All      Earrings    Loose        Other
         grade        rings                 Diamonds    Jewelry
         D, E, F        15         9           10           9
         G, H, I        68        61           65          70
         J, K, L        16        24           23          17
         M, N, O         1         6            2           4
    Unit sales of _engagement_ diamonds by color (JKC June 1991)
        GIA color
         grade      1976   1978   1981   1984   1986   1988   1990
         D, E, F      30     16     10      7     13     18     11
         G, H, I      58     62     64     72     61     61     61
         J, K, L      11     18     23     21     23     20     26
         M, N, O       1      4      3      0      3      1      2
       Median color    G      H      H      H      H      H      H

    7(e) Non-G.I.A. Color Grading Systems

    (You probably can skip this section, since everyone uses the GIA scale, but I've included it here just for the sake of being complete)

    Besides that GIA there are several different organizations that grade diamonds including the Belgian Diamond High Council (Hoge Raad voor Diamant, HDR), International Confederation of Jewelry, Silverware, Diamonds, Pearls and Stones (Confederation Internationale de la Bijouterie, Joaillerie, Orfevrerie, des diamants, perles et pierres precieuses, CIBJO), Scandinavian Diamond Nomenclature (Scan D. N.), the American Gem Society (AGS). Also, rarely, you can run across United Kingdom nomenclature, and others.

      GIA    AGS   Scan D.N. Scan D.N.  HRD     Old      UK      CIBJO     
                   <0.50ct    0.50ct+           Names 
      ---    ---    -----    -----    -----    -----    -----    -----
                                      Except'l          Blue    Except'l
       D                               white   Jager    white    white
              0                          +     -----    -----      +
      ---                    River    -----                      -----
                                      Excep-                     Excep-
       E     ---                      tional            Finest   tional
                                      white    River    white    white
      ---                    -----    -----                      -----
              1                       Rare                       Rare
       F            White             white    -----    -----    white
             ---              Top       +                          +
      ---                  Wesselton  -----     Top              -----
                                      Rare   Wesselton  Fine     Rare
       G      2                       white             white    white
      ---    ---             -----    -----    -----    -----    -----
       H      3            Wesselton  White  Wesselton  White    White
      ---    ---    -----    -----    -----    -----    -----    -----
                              Top               Top     Comme-  Slightly
       I      4             crystal           crystal   rcial    tinted
                   Slightly          Slightly           white   white(I)
      ---    ---    tinted   -----    tinted   -----    -----    -----
                    white             white              Top    Slightly
       J                    Crystal           Crystal   silver   tinted
              5                                          Cape   white(J)
      ---           -----    -----    -----    -----    -----    -----
       K     ---                                       Silver    white
                                                        Cape      (K)
      ---           Tinted    Top     Tinted    Top     -----    -----
              6     white     cape    white     cape             Tinted
       L                                                Light    white
                                                        Cape      (L)
      ---    ---    -----    -----    -----    -----    -----    -----
       M                                        Cape
      ---     7               Cape             -----    Cape     color
                                                Low                1
       N                                        Cape
      ---    ---             -----             -----    -----    -----
      ---                                       Very
       P      8                                yellow
                             Light                               Tinted
      ---                    yellow                              color
                    Tinted            Tinted
      ---    ---    color             color
      ---                    -----                      Dark     -----
      ---     9
      ---                    Yellow                              color
      ---    ---                               Fancy
      V-Z     10
      ---    ---    -----    -----    -----    -----    -----    -----

    7(f) Colorimetric Readings Vs. G.I.A. and A.G.S. Scales

    The GIA scale seems linear with the color compared to a colorimetric scale, but the AGS scale does not. The border between the _lowest_ named color (i.e. if a stone has a reading of 1.01 on colorimeter, it is F, whereas 0.99 is E) and a colorimetric reading:

            GIA  Colorimetric                   AGS  Colorimetric
           scale   reading                     scale   reading
             E       1.00                        0       0.75
             G       2.00                        1       1.35
             I       3.00                        2       2.00
             K       4.00                        3       2.50
             M       5.00                        4       3.00
             O       6.00                        5       3.75
             Q       7.00                        6       4.50
             S       8.00                        7       5.50
             U       9.00                        8       7.00
             W      10.00                        9       8.50
                                                10      10.00
    (Source: The Jeweler's Dictionary)

    7(g) Fancy Colors

    7(g) (1) Fancy Colors: Intro

    Once again folks, this entire section deals only with FANCY colored diamonds, i.e. a specialty, that you'll rarely run across, and are not marketed as diamonds that one would put into an engagement ring. Fancy colored diamonds are those diamonds that have colors beyond the white to yellow color, as is indicated above. One may obtain virtually any color diamond desired, if one can afford it. You should remember, that aside from the champagne diamonds, fancy colored diamonds are exceedingly rare, and with a price tag to match.

    7(g) (2) Fancy Colors: Judging the Value

    Color is the most important C in a fancy color diamond--color composes about 60% of its value. A cert should list the color of the diamond, the secondary color, and whether the color is natural or due to a treatment. The price of a particularly colored diamond however varies widely; a stone that is slightly differently colored may be valued at ten times a similar stone. A cut of a fancy colored diamond is also important: since the regular brilliant cut of a fancy color gives a too pale a stone, so a thicker cut is needed. Neither weight, nor clarity is very important (about 3 grades: IF, VVS/VS, and SI) in these types of diamonds (JCK Oct 91).

    7(g) (3) Fancy Colors: Sources of Color

    "Depending on the impurities present in the diamond and on the technique used, irradiation sometimes followed by heating can produce yellow, brown, green blue, or, very rarely, pink colors. These are not necessarily all color centers and are to be distinguished from the boron-containing blue nitrogen-containing yellow and green diamonds. ..." --Kurt Nassau, The Physics and Chemistry of Color: The fifteen causes of Color, Wiley-Interscience, 1983.

    Color in naturally colored diamonds comes from the substitution of different main group elements for carbon. For example, nitrogen substitution will lead to yellowing or greening of a diamond. Naturally blue diamonds contain small amounts of boron.

    There are two ways that a diamond can have fancy color, one is natural color, and the other is by irradiation of common diamonds. Irradiation of diamonds is controversial treatment, because of fear of residual radioactivity that the diamond may have might be dangerous to the wearer. I guess steady dose of radiation may not be deemed too romantic. However, the method that gave residual radiation (by using radium salts) is not used today, and the Nuclear Regulatory Commission sets the standards for radiation levels of diamonds. (JCK, May 93) I don't know what the level is in the US, but in Germany it is 0.07 bequerels. It appears that the GIA screens diamonds for radioactivity as a part of their testing. (JCK, Aug 92) No diamonds sold in the US are radioactive.

    The types of irradiation treatment used today include nuclear reactors, gamma ray facilities, and most often linear accelerators. It seems to me, that you just need a high energy source to knock out the carbon atoms out of the regular lattice into interstitial positions, hence creating F-centers. Dunno, according to the literature (e.g. JCK May 93), this type of treatment is stable, but I'd suspect that if the diamond is annealed that this color may disappear--hence, I'd tell your jeweler to be careful when mounting an irradiated stone.

    Hydrogen rich diamonds have recently been discovered in the Argyle mines in Australia, and in Jweneng mine in Botswana. The presence of H is detected by IR, and though the literature is silent on this, I suspect that it is interstitial defect, rather then substitutional one. Most common colors are gray, brown and yellowish, but blue (non-electric conductive) and violet (never seen before) are also present. (JCK Jun 91)

    Fancy color has also been generated by using backings. A backing is when the reflective colorless metal behind the diamond in the setting is painted. Because it is easily detectable, this method is rarely used today. However, some older pieces of jewelry may have this, so if you buy an old ring with a colored stone (even if it is not claimed to be a diamond, but some other precious stone) always make sure to have the stone taken out and see that there is no backing. (JCK May 93)

    Another source of color in fancy colored diamonds which you might run into (though rarely used) may be coating. The pavilion of a diamond is coated by some sort of a dye (food, fabric, ink, etc.), usually resulting in a desirable hue. You can identify a coated diamond if you look under the microscope at a pavilion side; coated diamond may exhibit an irregular or unnatural surface, and the dye may concentrate at some junctions, or may be chipped away. Personally, I'd just dip it into acetone, or nitric acid, either one should take care of pretty much any dye. Of course, as with any other treatment, the seller is under obligation to inform the buyer of the coating. (JCK May 93).

    As an aside, those of you who are physical chemists, it is possible to coat a diamond by chemical vapor deposition (2 micron layer), as has been done in the GIA research labs to generate blue diamonds. (CVD, or OCVD, of course, has been used in academic, and research settings for decades). Standard electrical conductivity tests of so treated diamonds can't be used, since the coating itself is conductive. Thermal conductivity tests, which test a bulk property, need to be used instead (JCK, Aug 91).

    7(g) (4) Fancy Colors: Color Overview

    a. Champagne (or brown) diamonds

    In the late 70's diamonds were discovered in the outback of Australia. Today, about a third of diamonds (by weight) mined come from this part of the world. Only one problem: they are not white, but brown. Though most of them are used for industrial use, some are of good enough quality to sell as gems (6% by volume, 50% by value). It is difficult to sell these brown stones, since everyone is used to the "the whiter, the better" rule DeBeer's has been pounding into their heads for decades. Argyle Diamond Sales, the organization both mining and marketing these stones, has been pushing them in marketing campaigns as "champagne" diamonds independent of DeBeer's campaigns pushing colorless diamonds, spending about 3% of their $300M annual revenues. It seems that the end consumer is someone who likes diamonds, has several of them already, and wants something unusual, more high-end fashion jewelry type diamond. Hence, it is NOT designed as an engagement diamond, which Argyle freely admits. Color grades of browns which are beyond the D-Z GIA scale, is C1 (very light brown) to C7 (dark cognac color). BTW, I'll give you one guess--who is the sole buyer of all of Argyle's production?.... that's right, the CSO. (JCK Jan 91)

    b. Blue diamonds

    There are some instances of blue diamonds, such as the Blue Hope displayed in the Smithsonian. A diamond is a semiconductor. A naturally blue diamond is doped with boron, thus holes, hence is a p-type semiconductor; increase in conductivity is a reliable way of differentiating the naturally color blue diamond from an irradiated one. Hence the rule in industry is: conductive = natural and nonconductive = irradiated (unless you come across a hydrogen rich blue diamond (a natural, nonconductive blue), or CVD blue (a treated, conductive blue), which would give you a false negative and false positive results respectively). And no, I don't know why they have a problem with a doing this with a nat. green, which is N doped, hence a n-type semiconductor.

    c. Green diamonds

    Green diamond pose a problems in treatment detection. There is no reliable way of determining if the color is produced naturally (like the famous Dresden Green), or if it is produced by irradiation. (JCK, Sept 89)

    d. Pink diamonds

    This is probably the most expensive (excluding the one-of-the-kind diamonds) colors for a diamond to have. They are minded, along with other colored, less exciting diamonds, in the Australia's Argyle mine When a couple of dozens are extracted after months of intense mining work, they are flown on a world-wide tour. The very best are sold at Christie's auctions, the rest are sold through offices in Perth, and Antwerp. Some description of pink diamonds recently mined:

    1 purple-pink 3.14 ct, $1.15M Apr 89 (JCK Nov 89)
    13 pinks, total $551K Apr 89 (JCK Nov 89)
    67 pinks 0.4 - 2.7 ct, total 64.13 ct, $6.9M total, Nov 89 (JCK Jan 90)
    36 pinks, total 40.93 cts, over $2M total, (about $80K/ct for diamonds < 1.5 cts and about $100K/ct for 1.5+ cts) (JCK Dec 90)

    e. Red

    There are more fingers on your hand then there are known naturally colored red diamonds. If you are buying one, congratulations!

  15. Clarity
  16. 8(a) General Info

    Clarity is a measure of how much and how many flaws there are in the diamond. Every diamond that you will see has some sort of a flaw in it. Flaws are natural; again remember that diamonds are mined and not manufactured, as opposed to the vast majority of items that we in modern times buy, which we expect to be totally without blemishes of any kind. Never the less, fewer the flaws, more valuable the diamond.

    And again, as for color, there are several grading systems developed, of which you'll encounter most likely only the GIA's. From the least amount of flaws (or inclusions), the scale goes from Flawless (FL), Very, very slight inclusions (VVS), Very slight inclusions (VS), Slightly imperfect (SI), and imperfect (I). These grades are further subdivided into classes with a subscript 1 or 2, thus the overall scale looks like:

    FL - IF - VVS1 - VVS2 - VS1 - VS2 - SI1 - SI2 - I1 - I2 - I3

    The I diamonds have inclusions which, by definition, can be seen by a naked eye. You need to take a look at a few of them before you will start seeing them if you are not used to looking at diamonds. Rest of the grading is done under a 10x microscope. You need to practice looking through a microscope, and most of jewelers have them. I wouldn't bother going to jeweler who doesn't have one, or who'll hand you a loupe; loupes are difficult to handle compared to a microscope. If you can see inclusions within, let's say, about 5 seconds, then it is a SI diamond. If it takes you a long time to find any inclusion on your own, assuming you are comfy with microscope, then it is a VS stone. VVS2 means that it is difficult for an expert to find an inclusion from the top of the stone, and VVS1 from the bottom of the stone only. IF, internally flawless diamonds have no observable internal inclusions, only some on the surface that could be gotten rid off by polishing the diamond some more at the expense of weight. FL diamonds are again extremely rare, there are only about four hundred 1 ct. FL diamonds produced per year worldwide.

    There are a number of types of flaws, or inclusions, that you'll see when you'll look at a variety of diamonds. As stated previously, the number, size, and location of flaws will determine the clarity grade. Most common are white specks, called pinpoints. These are found in almost all diamonds. Sometimes you'll find dark spots, or "carbons" (yes, they are just called that because it reminded the early mineralogist of coal).

    Common faults, that usually pull the grade of the diamond the most are feathers. They are small cracks that look like feathers, which are usually not a problem. They due become a problem if they are large, and if they break the surface of the stone. I'd recommend NOT to buy a diamonds where the feather break through to the surface, but internal feathers are harmless. And of course, exposing them to thermal shocks, or ultrasound, as with any other crystalline material, might enlarge a serious feather.

    Another fault that you might run across is a clear crystal growth. Although it is penalized just like any other inclusion, I find some pretty neat looking, and they give the diamond a sort of a unique character ("look at that baby crystal inside the diamond!").

    8(b) Clarity Enhancement

    Please note: I would not recommend getting a clarity enhanced diamond as an engagement diamond, but am presenting it here for the sake of completion.

    Clarity enhancement is a process in which a stone with poor clarity (let's say I1 or worse), but otherwise a nice stone, is treated to fill in the cracks. The exact identity of the material is kept a secret, but it is most likely some sort of a leaded glass. Obviously, it has to match the refractive index of diamond very closely. The durability of it is still in question... There is no problem with it what so ever in everyday wear; it is stable in boiling water, to shocks, etc. Filled diamonds (i.e. clarity enhanced diamonds) don't stand up to boiling HNO3, to direct heat (the jeweler must be careful when setting the stone), or to short UV (though it is estimated that it will take about 60 yrs of direct sunlight before it becomes noticeable; "diamonds are for ever"? maybe, but not clarity filled ones, though it should last a several human lifetimes if worn normally).

    Grading of filled diamonds must be done before the process. GIA wont grade filled diamonds; they insist on removing of the filling. Hence the clarity is assigned as I1 or I2, but the stone looks like VS, and thus nice-looking stones can be had cheap. But do not be mislead to think that enhancement is something special, that only the best diamonds, are enhanced, or that you have to pay extra for enhanced diamonds. Just the opposite. The idea is, again, nice looking stones cheap.

    There has been a lot of discussion on whether or not filled diamonds should be sold along with other diamonds, or whether they should be viewed in the same light as "lab grown" or "created" precious stones, though nobody would consider them as "fake" as let's say cubic zirconium. Everyone agrees though, that it is really important to reveal to customers (both the consumers as well as retailers) that a diamond has undergone the filling treatment. The worst fear of the jewelry industry is that the consumers will feel cheated, deceived,... and will stay away from diamonds. As stated previously, members of the jewelry industry absolutely must be meticulously honest; after all, nobody needs diamonds to survive, it is a luxury item.

    The policy on whether or not to stock filled diamonds varies from store to store. Some "don't want any of that crap in my store" others see it as a way sell customers what they want: nice stones cheap.

    If you look at a filled diamond closely, rotate it under light, you should be able to notice a bluish or an orangeish flash. Actually, there are new fillings that wouldn't make these flashes, but the manufactures worry that unscrupulous sellers would pass these as higher quality stones. Obviously, they also worry about the possibility of lawsuits. There are currently two firms who manufacture and distribute filled stones, Yehuda, the originator of this process, and Koss. Both firms offer top notch guarantees that if the filling is ever damaged (through a clumsy jeweler, for example) they'll refill it free. So it looks like a customer wont get stuck with a damaged diamond, ever. The question of durability, stability never enters into the buyer's consideration, and is thankfully shifted to the manufacturer.

    However, few people think that clarity enhanced diamonds will be sold for engagement rings. In part it may be because an engagement diamond is a "special" stone, only the "best" will do (and a diamond that needs to be filled can't be considered the best, can it?). I am not sure, but it seems that clarity enhanced stones are used more for purchases later in life for pendants, bracelets,... . Later in woman's life, when she has more disposable income, she is more likely to buy a diamond for herself than get it as a present (this is not my guess, that is what surveys show); it's OK to buy a nice filled diamond for herself, but may not like receiving it as a gift.

    But, cynically, I also suspect, that in part why they are not pushed as engagement diamonds is due to the fact that "it is a rule that bride-to-be must get a diamond engagement ring", thus the retailers can tell the groom that "real, unfilled" diamonds are the only way to go, and hit the groom for all he's worth. When the question is "filled or unfilled," the jeweler will of course push the unenhanced, and more expensive, stones. For a woman who wants to splurge after getting a big pay raise, the question wont be filled or unfilled, it will be "a diamond or a vacation or new furniture or ...", hence a jeweler will need to convince her that she should buy diamond jewelry, and if it is clarity enhanced, so be it.

    So, should you buy a clarity enhanced diamond? If you want a nice looking, inexpensive, real diamond, and don't care that the report says it should look worse, then buy it. But if you think that somehow you are cheating, and if this will bother you in the future, then pass. The choice is obviously yours. The bottom line is: if you are going to be happy with the diamond, then buy it.

  17. Cut
  18. Cut is the most important C, as far as the esthetics go, but the least understood C by customers. There are two different aspects of "cut", one is the shape of the stone, and another is how well the diamond is cut into that shape.

    When diamonds are polished, the final product has many flat surfaces. These are called "facets". All facets have names, which I'll go into later on. When facet come together, they form "facet junction"s. Unfortunately, the nomenclature of diamonds is fairly limited; according to dozens of GIA graduates that I've talked to, there are no formal names of facet junctions. Worse yet, "facet junction" refers to both a line (formed by 2 facets) and a point where more than 2 facets come together. When describing facet junction, I'll use terms from geometry: I'll call the former an edge, and the latter a vertex.

    9(a) Shapes of Diamonds

    The most common shape of all is the round brilliant. I will talk about that shape later on... Other common shapes are:

    Other cuts you might encounter maybe named after a variation of the ones listed above. Some may be named after royalty titles (princess by far the most common, but others like duchess, etc. are available), or after flowers (tulip, rose, sunflower,...), or whatever. Smaller cut diamonds that are placed into rows in a setting, which look like small boxes, or like tapered boxes, are called baguettes.

    9(b) Round Brilliant Cut

    The most common, and the most expensive, is the brilliant cut, a.k.a. the round cut, etc. Back at the turn of the century, when cutters were looking to cut the stones into the best shape, Marcel Tolkowsky, a member of a large and powerful diamond family, did the calculations on this subject considering all variables, such as index of refraction, covalent bond angles, etc., as a part of this PhD thesis in Mathematics in 1919. You might also run across this cut as the American Ideal Cut, or American Standard cut, etc.

    Although it is best to get yourself a picture of a diamond, let me try to draw it here in ASCII as viewed from the side:

                   ------          <-- Table      ---
               /           \       <-- Crown       /  16%
              ===============      <-- Girdle     ---
               \           /                       /
                 \       /         <-- Pavilion    /  43%
                   \   /                           /
                     V             <-- Culet      ---

    9(c) Depth (or Height) of the Diamond

    Now, Tolkowsky's cut's height is 59% that of the diameter of the diamond. which breaks down to about 43% for the pavilion, and 16% for the height of the crown. This 59% is probably the most crucial dimension of the stone. You might find diamonds that are both too shallow (i.e. the height is significantly smaller than 59%), and sometimes you'll see stones that are too chunky ( significantly over 59%). Since this dimension is the most important one to the brilliance, don't buy any stones that deviate too much from this value. You will sometimes see other standards like the Eppler Cut, and the Scandinavian Cut, that look just like the Tolkowsky Cut, but the height is at 58%.

    9(d) Table of a Brilliant Cut

    Probably the most noticeable proportion on a Brilliant Cut diamond is the size of the table. The size of the table is important, because it determines the look of the stone: bigger the table, greater the brilliance (the sparkle) and less the fire (the variety and intensity of the color reflected); smaller the table, greater the fire and smaller the brilliance. It is more wasteful to cut the rough diamonds to have smaller tables, thus diamonds with smaller tables are rarer. Tolkowsky has found the table to be ideal at 53% (again, of the diameter of the stone), but the Eppler Cut and the Scandinavian Cut have tables at 56% and 57.5% respectively. The appraising guidelines penalize diamonds with tables above 64% pretty severely, but when you go shopping, you'll see tables all the way into 70's. Ugh! Personally, I like the table to be at upper fifties.

    9(e) Crown

    (This is difficult to explain without pictures)
    The table is octagonal. Each edge of the octagon has a triangular facet adjacent to it, called a star facet. Two sides of neighboring star facets make two edges of a four-sided facet called a kite facet. One vertex of a kite facet is also a vertex of the table, and the opposite vertex is on the girdle. Now, the triangular area of the crown between the bottom edge of one kite facet, bottom edge of the neighboring kite facet, and the girdle, is divided radially into two entiomeric triangular facets called upper girdle facets. Hence, we have one table, eight star facets, eight kite facets, and 16 entiomeric upper girdle facets, for the total of 33 facets.

    9(e) Girdle

    Girdle is the widest part of the stone. Traditionally it has been left in rough, so it looks like a ground glass. However, in the past few years, a lot of stones coming out of Israel have faceted girdles, 32 facets all the way around. You might also, rarely, see polished girdle. Some people though stay way from diamonds having polished girdles, since the majority of fakes tend to have polished girdles.

    Whether the girdle is faceted or rough, does not have any relationship on the value of the diamond. Again, it is just a personal preference. Now, a jeweler might tell you that a diamond with faceted girdle is more pretty, which may be true, but the price should not be effected.

    9(f) Judging the Crown

    It is important that the edges of the facets come to nice, pointed vertices. Having another vertices by pentagonal kite facets and quadrilateral star or UGF is really undesirable. And of course, having extra tiny facets is a no-no as well.

    Also a smaller point to consider when judging the crown, is where the vertex where a star facet, two KF and two UGFs (the only vertex on the crown which is neither on the table nor on the girdle) come together, is located. It is suppose to be half way between the table edge and the girdle.

    9(g) Judging the Table

    If you look at the crown and ignore the kite and upper girdle facets, you'll notice the star facets and the table to make a design that looks like two staggered squares. Make sure that it indeed does look like squares with straight lines, or better yet, it looks 'bowed in'. If these squares look like they are bowed out, then you have a large table. Actually, Tolkowsky Cut has them bowed in. Thus buy a diamond that does not have the table bowed out. However, be careful that this considers the vertex described above is indeed halfway between the table and the girdle; some stones are cut so that these vertices are closer to the girdle, thus achieving a bowed in look even with a large table.

    9(h) Judging the Girdle

    The girdle should not be too thick or too thin. Obviously, the more uniform around it is the better. Numerically, I'd say that the girdle thickness measures between 1 and 3%, but numbers are generally not used. On GIA certifications, you'll only get qualitative 'thin, 'medium', etc. or a range, such as 'very thin to thin'. Stay away from diamonds having a sharp, knife-edge girdle; this might present a problem during mounting or wearing, and the diamond might chip. A thick girdle is a place where a lot of weight might be hiding; I've calculated that for each percentage point of extra girdle, the weight of the diamond increases by about 4%, if the other parameters are held constant. Hence two stones that look alike size-wise, but weigh slightly differently (ruling out fakes, of course), size of the girdle is the first place you might want to look at.

  19. Prices
  20. 10(a) General Info

    Yeah, good luck trying to get some sort of a price table out of a retailer. This keeping of prices a secret really makes me angry. The standard line when you ask for prices is: "tell me which diamond you want, I'll get it for you, and I'll tell you the price." If you ask a retailer for a matrix of prices, or a formula on how to determine a price they'll look at you like you are from Mars. The truth is, actually, that they don't know; they just get a stone from a dealer for a set price, and just add 50 to 150% to it, and charge that to the consumer. Yes, if you know anything about marketing, this is a pretty crude and unsophisticated method of setting prices within a value chain, however, that's what they do!

    Nonetheless, there is a publication that does survey wholesalers and sends their findings in a weekly newsletter, called the Rapaport Diamond Report. The price tables themselves take up several pages. The company that puts the RDR out are located at 15 W 47th Street, New York, NY 10036. You can call them at 212-354-0575, and ask them to mail you an issue of their newsletter, or fax you the price tables for the cuts you are interested in. The price for this is about US$20, well worth your money if you are serious about finding out how much diamonds are worth.

    The prices quoted in the Rapaport are in hundreds of dollars per carat (which is equivalent of dollars per point, obviously), for a well cut stone. Appropriate deductions of poorly cut stones need to be taken into account when trying to establish a price. Also, the quotes are wholesales, "...but most consumers who get a hold of RDR don't realize that these are high wholesale prices, and a retailer can get the stones for 30% less, especially in the bigger sizes" (paraphrased from JCK)

    Well, here is a sample (actually, each table below is 11 by 10, not just 5 by 4, and there are 18 such tables, not just 8) of what you'd find in Rapaport for 21 Oct 94 for round cut stones (remember: well cut, in hundreds of $/ct). Sorry, I don't have a more recent issue....if you like my FAQ, please get the more recent edition, update what I've posted below and e-mail it to me. The prices since then have been held pretty constant, though.

        ------- 0.30 to  0.37 ct -----       ------ 0.38 to 0.45 ct ----
            VVS2  VS1  VS2  SI1  SI2         VVS2  VS1  VS2  SI1  SI2
         F    35   30   23   19   17           38   31   27   22   20
         G    30   27   22   18   16           33   28   26   21   19
         H    23   22   19   17   15           26   24   22   20   18
         I    20   19   17   16   14           23   22   21   18   16
        ------- 0.46 to 0.49 ct ------       ------ 0.50 to 0.69 ct ----
            VVS2  VS1  VS2  SI1  SI2         VVS2  VS1  VS2  SI1  SI2
         F    40   32   28   23   21           46   42   37   30   24
         G    35   29   27   22   20           42   40   35   28   23
         H    30   25   23   20   18           36   34   30   27   22
         I    25   23   22   18   17           30   27   25   23   21
        ------ 0.70 to 0.89 ct ------       ------ 0.90 to 0.99 ct ----
           VVS2  VS1  VS2  SI1  SI2         VVS2  VS1  VS2  SI1  SI2
         F   48   44   42   38   33           51   47   45   40   35
         G   44   42   40   36   32           47   45   43   39   24
         H   42   40   38   34   30           45   43   41   38   33
         I   37   36   34   32   28           41   39   37   35   31
        ------ 1.00 to 1.49 ct -----        ------ 1.50 to 1.99 ct ----
           VVS2  VS1  VS2  SI1  SI2         VVS2  VS1  VS2  SI1  SI2
         F   66   59   55   51   44           77   66   62   56   48
         G   59   55   52   49   43           66   62   58   53   46
         H   55   52   49   47   41           60   58   54   51   44
         I   52   49   47   43   39           56   53   51   47   42
    This means that a well cut 64 point VS1 H round brilliant diamond would cost $3400/ct * 0.64 ct = $2176 according to this issue of RDR.

Page last modified: Sunday, May 16, 2004

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