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The Diamond Grading Four C's
A practical guide you can actually use!
In diamonds there is a rich and diverse choice of shapes, each has a different way of working with the light. The range of cuts available are wonderful, but it is true also there is not another cut that sparkles like the round! The Radiant Cut comes the closest of the squares, but all shapes, in the right cut, are outstanding! I will review some of the more popular cuts as I go on, and will also explain a bit about what the cut paramaters should be and some important things to consider about each of the cuts and shapes. When I refer to the term that a diamond should be "Well cut" I mean that it's geometry and finish, symmetry and make should be perfectly fine, many still do not realize that for diamonds the "CUT" best refers to the shape, at least in relationship to the "Four C's" that is...

The Round Brilliant
The most common, and most "brilliant", diamond cut is the Brilliant Cut, a.k.a. the Round Cut, American Ideal Cut, or American Standard Cut. Back at the turn of the century, Marcel Tolkowsky, a member of a large and powerful diamond family, calculated the cuts necessary to create the ideal diamond shape. As part of his PhD thesis in mathematics, Tolkowsky considered variables such as index of refraction and covalent bond angles to describe what has become known as the brilliant cut. A large table (over 64%) can really kill the diamond's beauty, and a stone which it too shallow will also "die optically"... Where a great place to be is in the 58.5-63.5% depth, and a table size in the mid fifties, but to about 60% safely for beauty.



"Screwy Cuts" are discounted heavily they are also much less beautiful as well, so make sure you are comparing apples to apples... Stones with deeper cuts, or larger tables will be discounted, but you can be sure that if you confirm to a narrow range of specs we've discussed here that you will do very well. I really like some stones which have table sizes up to 60%, and often times the visual difference between an AGS (000) ideal cut, and fine premium cut with a slightly fuller depth or table size just out of range is practically nill, when the price difference is vast... Beauty to me is taking the five C's into harmony, cut, color, carat, clarity and "cost"... While I really like the table sizes in the mid to higher fifties I'm a sucker for a 57.8%-60% table on a stone that is both well priced and beautiful... Great diamonds and beauty exist acoss a ample and wide range, and that is also where maximum value lives too.

Marquise
Looks something like a football, when viewed straight down from the top. Some Marquise are cut too thin and suffer from a markedly dark center (commonly called the bow tie effect). This effect is eliminated by paying attention to the depth (want lower sixties).If you're offered a stone under 58% it will only look good under halogens :) If you can stay in the lower 60's in depth in your marquise this will relate to a larger size, deeper stone are often the same weight but will be of a much "smaller appearant size"..To me the loveliest shape in a marquise is 1.50-1.60/1 but many prefer a standard 2/1 ratio.. (I like mine shorter, rounder and chubbier like the football, rather than longer and pointier) For a bright stone watch that depth carefully!



Oval
Has an elliptical shape when viewed from the top. For both the Oval, the ratio of the length to the width should be about 1.5:1 but againn, shorter, rounder ratio's are very pleasing! If it is too long and thin then that you will see a dark area. This is commonly called a bow tie effect, "undesirable". If the ratio is much less then 1.5:1, the stone looks like a misshapen round. A well cut oval stone can be nearly as bright as a well cut round brilliant shape, the angles are closer to ideal for the maximum optical effect that well cut diamonds can produce... Trust your eye to judge the cut, if an oval shape looks lifeless in natural light odds are it's a very poorly cut stone.... (No fair cheating with dozens of recessed halogen lights in the retail store :) Stay with lower sixties in depth for this cut.

Emerald Cut
Looks like a rectangle from the top, with truncated (cut)corners. These can be beautiful stones, with stepped facets the sheen tends to be large flashs of these stepped angles on the pavilion of the stone... With this cut I feel that color plays a very important role in the beauty off the stone, color tends to show very dramatically in emerald cut stones so stay up above "J" for a super look.

Ratios to vary greatly in fancy shape stones, which tend to be cut to maximize the diamond crystal, so you could say that the stone "tells" the cutter what shape it wants to be to yield the largest and most precious finished stone... Stay about also in the sixty percentile range depth here, with a 1.5:1 aspect ratio for a great standard look. Modern stones and lovers of a square look commonly favor ratio's of a 1.30/1 average. Another consideration is clarity in the emerald cut, since it's a step faceted stone you won't hide imperfections easily in this cut, you should stay in the VS1-2 range to know 110% that the stone will be eye clean, however, there are many stones to be had in a GIA graded SI1 that your eye needs a loupe to be able to find the flaw! That's what I'm here for :) To aid in finding those great stones at a great price point!

Pear Shape Cut
A popular cut that looks like a tear drop. This is a traditional cut which is perfect for pendants, drop earrings and many applications. Remember that really excess weight will cost you appearant size, so watch that depth percentage. Also watch that depth here too folks! You want to make sure the stone has good depth as well, a shallow stone is not only more dangerous than a well cut stone, it's also not nearly as bright. Once again it's the critical angles and reflection of a well cut stone that's the key to its beauty... Stay 61-64% here in depth, and head for that 1.5:1 aspect ratio for a great look and lively diamond. Color also shows fairly dramatically in a pearshape cut; all fancy cuts tend to show lower colors more significantly than a well cut round stone... Do not buy a stone less than 58% for the optics will be seriously a problem in this shallow depth.

Trillion Cut
(Or variations of this spelling) are three sided cuts.... Many of these cuts are trademarked cuts. The triangle cut tends to be a stepped facet cut while the "Trillion and other variations of this more modern cut are based upon a brilliant style cut... The fire and beauty of these cuts is spectacular, they are wonderful cuts... Trillions are basically triangular in shape, usually with truncated corners, with a variety of facets. Depth here is OK through the mid to high sixties ( 61-68% ) but avoid deeper or shallower... Don't be put off by seemingly huge tables, a 70% in no problem in this cut.

Square Radiant, Asscher, Cushion & Princess Cut
As discussed earlier, the Radiant cut is patterned off of the round cut, thus a square radiant, in my opinion, is almost, as brilliant as a round....and my first pick for a square cut stone. Depth's and tables should be in the sixty to lower 70 percent ranges in all square stones. Princess cut is the most commonly sold square shape (Thank you to the "mall") so many people who start at those types of stores don't often have the opportunity to see radiants, asschers, and finely cut cushion cut diamonds. Cushion's have a huge variety of what the stone can look like, large flat and square, square with a very high crown, oblong and very rounded, etc. Its easiest to assist in finding a cushion cut diamond when YOU know what shape you're after so I can ensure you receive the shape you want to see!