The Scintillating Dance of Light

If you ever had even a superficial brush with the dazzling world of diamonds, you would have heard of the 4 Cs: carat, colour, clarity and cut. But do know that cut is considered second only to carats in determining the value of the stone?

In gem-speak, cut is the act of creating symmetrically arranged flat facets by cutting and polishing a rough gemstone. Experts say that cut must not be confused with shape: while shape refers to the stone’s exterior appearance (pear, oval, round, and so on), cut is about symmetry, proportion and polish, in short – about the gem’s reflective characteristics.

By placing each and every facet in a precise geometric relation to one another, the cut determines the brilliance and durability of a diamond. A perfectly cut diamond is bright and sparkling because light strikes every surface at the correct angle, thus creating the mesmerizing play of reflections and refractions.

A well-cut diamond accepts light at the top, bounces it from one side to the other, and, when it hits the base, shines it back out. To an observer it looks like a dance of a brilliant fire that diamonds are famous for.

All that sparking illumination come with a price: after all the cutting and polishing, a diamond crystal usually loses at least 50% of its weight.

A diamond's cut is evaluated by trained graders. Higher grades are given to stones with symmetry and proportions that most closely match the ideal. This ideal differs from region to region and from a gem appraiser to gem appraiser. The cut can receive an assessment of excellent, very good, good, fair, and poor.

Here are some of the most popular modern diamond cuts:

Round brilliant cut is most likely to be used whenever the shape of the crystal allows it. It delivers the most brilliance and is best at hiding flaws and yellow colour. To be accepted as a brilliant, the cut of the stone has to adhere to strict rules, perfected by both mathematical and empirical analysis. A classic round brilliant cut diamond has 58 facets: 33 on the top, 24 on the bottom, plus the culet (1 point at the bottom). 

Every diamond cut that is not brilliant is called a fancy cut.

Fancy cut is usually applied to oddly shaped crystals. The exact cut depends on the crystal and on the current fashion trends. Most diamond fancy cuts can be grouped into four categories: modified brilliants, step cuts, mixed cuts, and rose cuts.

Modified brilliant is the most popular category of fancy cut. Modified brilliants include the marquise or navette ("little boat" in French), heart, oval, pear, water-drop cut, and so on.

Step cut produces square or rectangular stones with parallel facets. This comparatively shallow cut cannot match the brightness and fire of a brilliant. Instead, step cuts emphasise diamond's clarity, whiteness, and lustre. The most popular step cut is the slender, rectangular baguette. Emerald cut looks similar to baguette, but emerald can be either rectangular or square and has more facets (50 to 58, in comparison to baguette’s traditional 14).

Other popular step cuts include trilliant, kite, lozenge and trapeze.

Mixed cut aims to combine the characteristics of both (modified) brilliant and step cuts, that is – to achieve the brilliant-like fire without sacrificing the size of the stone. Mixed cut stones were introduced relatively recently, in the 1960s. Barion cut, invented by a South African diamond cutter Basil Watermeyer, is a square or a rectangle with 62 facets and the characteristic central cross pattern.  Radiant is a similar cut, but with a total of 70 facets.

Princess cut is the most successful mixed cut. It has higher fire and brilliance than other mixed cuts and wastes less of the original crystal than any other diamond cut. It has become so popular that some gemological labs have developed princess cut grading standards that are as stringent as the standards applied to round brilliants.

And the best cut is… a matter of personal preference and budget. People who love the sparkle will reach for the brilliant. Others prefer the elegance of emerald and baguette cuts.

In any case, if it’s a diamond, you can hardly go wrong.