Diamond Cut Factors

Cut The cut of a diamond can dramatically affect its price.  By cut we mean quality of cut, not shape of cut.  There are specific proportions and angles that are ideal for diamonds (just as there are for all gemstones).

A properly cut diamond sparkles (or scintillates) more, shows more rainbows, and is brighter (reflects more white light) than a poorly cut diamond. Why are diamonds cut badly   Most lapidaries (gemstone cutters) who get the chance to cut a diamond really know what they re doing. A bad cut is not usually the result of a bad cutter, but rather the result of a financial decision.  Cutting a diamond involves making it smaller, therefore making it weigh less and losing value (diamonds on average lose 60% of their weight during cutting).

Therefore, the diamond cutter s objective is often to maximize carat weight, sometimes at the expense of a perfect cut.  Therefore, when you find an ideal cut diamond, it is usually an indicator that the cutter (or the cutter s boss) made a choice to produce a more perfect stone rather than a heavier stone.

An excellent cut diamond is always more valuable (all else being equal) than a poorly cut diamond.  The quality of a cut is different from color and clarity because it is easier for you to evaluate.  You probably won t be able to say, No, the pavilion is too deep and there s a small extra facet here.   But you will see the difference in the sparkle and the fire.

Shapes of Cut

The most popular cut for a diamond is the standard round brilliant. This is because this cut arguably displays the rainbow and sparkle of the diamond the best.  Another cut that has become popular in the last decade is the emerald cut (also called baguette cut).  This cut was traditionally used for yep, emeralds, to maximize the display of the stones natural color.  Many people find this cut appealing because of the shape and because it maximizes the white light that is reflected.  This cut, however sacrifices the fire or dispersion and the sparkle.  Other cuts include_once the oval, marquis, pear, trilliant (triangle), square or princess, cushion, and fancy cuts (e.g. heart).  It is also popular for jewelry brands to develop their own signature cut like Asscher, Zales, Leo, etc.  The shape of the cut does not affect the price, except in the case of fancy or branded cuts.

Standard Round Brilliant
Emerald Cut or "Baguette"

Square or "Princess"

"Lone Star"
"Hearts and Arrows"
A final note about diamond shapes (style of cut).  When it comes to number of facets, more is better to a point, after which more becomes worse.  For example, a diamond with 52 facets will show more sparkle, brilliance and fire than a diamond with 24 facets.  But a diamond with 156 facets will show less sparkle, brilliance and fire. This is because each facet is smaller with less difference in the angle compared to the one next to it.  See pictures below.

58 Facets
88 Facets
137 Facets

Queries / Comments: 1

1. Manoj Kumar [02-04-2011]