A: Here are the basics. There are 4 Cs, not 5, in that catchy little DeBeers memory aid: Color, Clarity, Cut, Carat (weight)

• Color

  Color preferences are perhaps most important in your choice, regardless of what the market would like to sell you. Very white and colorless diamonds cost more than those with increasing degrees of a yellowish or brownish tint, which are much more common. The “whitest” stones will cost you several times what those with easily visible yellowish color will cost. Note, though, that diamonds do also occur in more desirable brighter colors, called “fancy” colors, which are sometimes exceedingly costly. These include any discernable tint of blue or green or pink, no matter how faint, and going quickly up in price as those colors become brighter and darker.

  A good strong pink, red, or blue diamond is going to be a very rare and expensive stone indeed, compared to the “white” colors. Even the yellow colors, once they become dark enough to be attractive yellows, instead of a dirty dishwater color, become expensive. You should also know that some ordinary diamonds can be treated with irradiation to cause fancy colors. These are often priced quite comparably with the ordinary white diamonds, and though not considered rare, give you another attractive choice.

  Diamond color grading is using a scale devised by GIA, which assigns the letter D to the finest, whitest stones. D, E, and F are considered one grade in smaller stones, and are only discernable from each other in larger ones, since it is just a slight difference in transparency. From there, as you go down the alphabet, the stones become increasingly tinted. G and H and maybe I are considered normal, fine commercial grades, with a G color being pretty nice, and an I color being usually quite acceptable, though nothing special. J is slightly tinted, but is acceptable to some folks, especially in mountings where yellow gold tends to mask the color in the diamond anyway. They also have the advantage that you’re getting the same size and quality in other respects, for considerably less money, so you can increase the size or quality if you have a fixed amount to spend and are willing to accept some yellowness.

• Clarity

  Clarity is simply the appearance of various inclusions and defects in the crystal. In general, this refers to natural artifacts of the diamond’s formation. Some are rightly termed “flaws”, but others, though they affect the value, can be appreciated for the individual character they can give a stone, a signature of mother nature, if you will. The difference depends on how large they are and how much they affect the appearance of the stone, as well as how much they affect its durability. It also includes those surface defects, including dings and chips, etc, incurred in wear and handling and use.

  Diamonds are graded for clarity under 10 power magnification, supplied by a good corrected loupe at least, but better, especially for you to see, with a good binocular microscope and someone helping you see what’s in the stone. The “best” is of course a flawless grade. This grade is not practical for a ring, as the chances of its keeping that grade in normal wear is almost nil. Keep the flawless stones for investment purposes, or at least, for jewelry that will get little wear. In fact, once mounted, no diamond can be graded flawless any more.

  The next grades are VVS 1 and 2. Stands for very, very, slightly included, and means exceedingly tiny and hard to find inclusions. The VVS-1 grade is, like the flawless grade, somewhat questionable for use in an engagement ring, since in many cases, it won’t be able to retain that high degree of clarity in normal wear. Still, at that point, the VVS grades will be right for some people who wish this high degree of clarity and rarity. next, the VS grades (1 and 2) are those stones with relatively minor inclusions. These are generally inclusions somewhat hard to see right away under 10×, down to not very hard to see, yet still not dominating the appearance of the stone under 10×. “Minor” inclusions is the keyword. These stones, I feel, are good choices for someone who wants a good clear looking stone, without paying for excessively high clarity. These stones will have inclusions, yet not those that much affect even the appearance under magnification. Yet the inclusions are still enough to give the stone some individuality as well.

  Lower still are the SI (slightly included) stones. An SI-1 is still a nice looking diamond, though the inclusions will be fairly easy to see under 10×. The SI-2 will have inclusions quite obvious under 10×, yet not normally seen with the naked eye, at least not in the face up position. Also a good choice, this range is, for those who want a nice clean look but no more than needed. Finally are the imperfect grades. These range from I-1, which are stones where the inclusions are only barely visible to the naked eye, to I3, where you find yourself asking not only how did they manage to hold the poor destroyed thing together while cutting it, but why did they bother. Some I grade stones, especially I-1s, can still be quite attractive stones, even with faintly visible inclusions.

  The whole thing to keep in mind, here, is that higher clarity costs you more, while lower clarity may make it possible to get a stone better in other ways. And, keep in mind that once you get to an SI-1 grade, all the higher clarity grades appear pretty much the same to the naked eye. Only with magnification can you tell any of them apart. Thus, the difference between high clarity and modest clarity is pretty much, in terms of a stones use and function in jewelry, a mental, emotional difference, rather than one that makes a difference in the beauty of the stone. Consider this carefully before you spend lots on a so called good clarity for more money. make sure this is a difference you are willing to pay for. It generally does not make a difference in the beauty or function of the stone, only in its price and relative rarity. (Note as well, that this is not the case with higher qualities of cutting or color or carat weight, all of which affect the stones appearance and beauty and appearance.)

  There are few absolute laws in diamond grading. While it is probably true that some otherwise SI2 stones, where the flaw breaks the surface, will be graded I1 as a result, This is not a law or automatic judgement. The key is likely to be whether there is any undue reduction in the durability or increased risk to the stone. There are many VS stones where the small feather happens to reach a surface. Often, it makes little difference. However, a larger feather, reaching a girdle edge, for example, might substantially increase the ease of breaking that stone over a similar stone where an identical feather is completely internal. Such a situation might easily warrant a grade reduction…The bottom line, in diamond grading, is that all stones must be individually evaluated. Follow your eye, and your brain, not merely the guidelines or definitions of the grades. Those definitions are, in a number of ways, a bit vague.

  Diamond grading is by nature, a subjective set of choices, rather than an absolute set of rules. What, for example is the difference between the “extremely difficult to see” VVS inclusion, and the “difficult to see” inclusion in a VS? You, and your eye, will know this easily with practice. Yet to absolutely define the rule is pretty hard to do. Cutting is where diamond grading gets tricky. It refers both to the general style of cutting the stone, such as its shape and the number of facets, etc, but more importantly to the optical qualities of the stone, based in large part on the angles at which the facets were placed, and the relative sizes of those facets. The aim is to produce a stone that looks symmetrical and has a beautiful and graceful shape, as well as one that’s most effective at reflecting light and refracting it.

• Cut

  There are various methods of grading the cut, but no one easy way to describe a set of grades, as there are several distinct areas of the stone that are graded separately. First off, be sure the stone just plain looks good. A round stone should be round, a pear shape should be a graceful shape, not lumpy or arrowhead shaped. Some heart shapes, for example. look more like a cartoon image of Wily Coyote’s head, with a pointy snout and long wild ears, instead of a graceful heart shape. In judging the optics, you want to see the whole stone evenly reflecting light, without any dark areas, or areas where you can see through to the mounting. This is largely a function of the pavilion, or bottom facets of the stone. Ideally, in a round stone, the depth of the pavilion, expressed as a percentage of the diameter, should be about 43 percent of the width for maximum brilliance or reflectivity.

  The crown, or top of the stone, consists of both the table facet (the top flat surface) and the crown facets proper. The whole crown needs to be high enough so that the crown facets can break light up into dispersed, spectral colors, and the table needs to be small enough that there is enough crown facet area to have a good effect. Generally, a table size of between 53 to 60 percent of the diameter of the stone will be attractive, with the smaller end of that range often being preferred. The crown facets should be at a 34.5 degree angle to the girdle. In fancy cuts, of course, some compromises need to be made, but the same general optical rules apply, even if the resulting measurements may differ.

  Here is where the aid of a competent gemologically trained sales person can be invaluable, showing you the visual differences between well-cut and not so well-cut stones. In addition to the simple factor of maximum beauty, however, you need to be aware that as with other quality factors, poor cutting has its tradeoffs. A “poorer” cut was usually done that way to allow the stone to be larger, given the rough diamond it had to come from. So though a poorly cut diamond may not be as attractive as another that size might be, it will often, for the same money, be larger. For some people, this is a desirable tradeoff.

  GIA diamond grading reports do not quite give sufficient proportion information to actually be sure of the cutting quality. With only a total depth percentage and a table diameter, and a girdle thickness, one can have “ideal” looking proportions that in fact describe a stone whose table is a good size, but with shallow crown angles and crown height, compensated for by a deep pavilion. Such a stone is obviously spread in appearance, and less desirable and costly, yet its numbers won’t divulge that fact. GIA is still the most prestigious lab in the country, but other labs in the US, (EGL, for example) do break down the depth into separate crown and pavilion measurements, or otherwise give enough detail to properly describe the proportions.

• Carat

  Diamonds are sold by weight, in Carats. Five carats equal a gram. A round one carat diamond is about 6.3 mm in diameter, which is sometimes referred to, especially in dealing with diamond simulants, as a one carat size. Remember, though, size is not the same as weight. A carat is also broken down into 100 “points”. Thus a 50 point diamond weighs half a carat. These points are simply decimal places of a carat, and not anything to do with little sharp edges, chips, or anything like that.

In closing, I should also mention that you need to be realistic about the marketing of diamonds. They are often marketed as rare, timeless, beautiful beyond comprehension, forever, or other such concepts. Keep in mind that much of this is hype, not reality. Diamonds are certainly one of the most unique gem materials we have, and capable of remarkable beauty. And though not indestructible, they are certainly one of the most durable and hardest to break or damage, so they are very well suited to jewelry use. But before getting too caught up in the rare bit, remember that there are enough of them to be priced like commodities in a competitive market, and that the prices of them are determined by an almost complete monopoly, not by true supply and demand. And then remember that every jewelry store on the planet has several thousand of them, or more, and often at least a couple pretty large and costly ones. Given all that, ask yourself how rare they really are.

This does not mean they are not beautiful or desirable, or not worth putting in your jewelry. It does mean, though, that you should ask yourself how much your desire for the diamond has been shaped by its real properties, and how much by the very successful marketing of the things over the last 75 years or so, perhaps the single most successful marketing campaign in history. Remember that prior to the discovery of South African diamonds in the late 1800s, most wedding/engagement rings did not have diamonds at all. And remember that until Hollywood started showing us (with DeBeers’ generous help) all the pretty starlets dripping in diamonds, the average American woman owned few if any diamonds. Prior to World War II, an engagement diamond a carat in size was a rarity. Even in the ‘60s, most brides got married with much smaller stones. Traditions in diamonds,, if you’re letting yourself be swayed by them, are rather recent and suspect things, carefully engineered for us by the good folks at DeBeers. Doesn’t mean they are not now valid and meaningful, especially if all your friends now follow them. But you should simply be aware of these things before spending large chunks of your income on one.

As to the two months stuff, please remember that this, like almost all “rules of thumb” and various other suggestions regarding engagement diamonds, is the bright idea of the marketing folks at DeBeers. Is any suggestion on how much to spend on a thing, when suggested by the sales people trying to get you to buy a product, worth anything more than a moment of caution? It’s just the latest in their marketing campaign to get us to spend more on yet bigger diamonds. In the ‘70s, it was common to see couples getting married with third of a carat and half carat diamonds. That seemed enough for many. But somehow, DeBeers wanted to sell bigger stones, for more money; hence the two months thing. Now, strangely enough, brides are wanting the carat size stones, which just conveniently seem to fall in that two months range for many young professionals.

And meanwhile, those less-desirable smaller diamonds seem to be marketed in other things, such as the anniversary ring, men’s jewelry, and that great “eater-up” of small diamonds for lots of cash at a time, the famous Tennis Bracelet. (That, just so you are clear on this concept, was yet another bright innovation from the folks at DeBeers.) Instead of that, figure out what you feel you can comfortably afford, keeping in mind that at least in theory, this is a long term purchase. Do this as well, with the notion that jewelry and diamonds are not financial investments. You should never (unless you’re in the business, of course) consider potential resale values or so-called investment values as anything other than a curiosity, in terms of making decisions to buy or not buy a given piece of jewelry, a diamond or other stones. Used diamonds are simply not generally salable at a profit, even over time. Scrap values received are better than nothing, but nothing to get too excited about.

The real values in jewelry are the investment in symbolism, in your own sense of self esteem, in the value of a gift, either to yourself or to someone else, or its value to you as a social symbol, or decorative item. These are the reasons we wear jewelry. For status, for symbolism, for personal adornment and to feel good. Those are the values to consider in choosing to buy a diamond. Don’t, however, take this to mean diamonds don’t have value. They do. They are a wondrous gem material, radically different from other gem materials in properties and durability, able to take and keep a much higher degree of finish and cutting perfection than other stones, and able to withstand a variety of setting techniques that would be foolish with many other materials. They are a quite unique material, well worthy of respect and desire. If you’re in love with the stone and just have to have it, then it may well be worth the price. If you’re buying it only because you feel socially obligated to do so, then there is almost no price that’s cheap enough, and you need to rethink your choice to buy a diamond. Marriages don’t actually depend on a bit of carbon on the bride’s finger to survive and prosper.