Diamond Cuts and Proportions

The proportions and symmetry of the cut of a diamond is extremely important to the brilliance, liveliness and sparkle of the individual stone. The different types of cut have different reflective qualities, some being very sparkly and some with a low key sparkle.

When a diamond has been ideally cut the light rays that go into the top of the diamond will bounce off of the facets and are reflected back through the top of the stone. So if the stone hasn’t been ideally cut this will effect on how the light bounces around it. If the diamond isn’t ideally cut then some of the light will escape out of the base or side of the stone and will not be reflected out of the top – hence the diamond appearing to have less liveliness or brilliance. If a diamond is cut slightly deeper than the ideal proportions the majority of the light that is lost escapes when it is reflecting from one side as it to the opposite side as it is reflected at an angle. However if the diamond has been cut more shallow than the ideal proportions the light is more likely to be lost through the bottom of the stone meaning that the eye can see a dull reflection of light.

Although most of the cuts tend to come in celebrated millimetre sizes this doesn’t mean that the carat weight of the stone will also be a particular weight, however if the stone has been cut ideally it is likely to be in a similar area for example a 4.5mm round diamond will weight around 0.34ct but it would depend on the individual stone to the exact carat weight. Fancy cut stones tend to vary more in millimetre size to carat weight due to the lapidary wanting to get the best out of each stone, thus sometimes needed the diamond to be slightly shallower or slighter deeper.

The most sparkly round cut is called the brilliant cut; the reason for all this sparkle is that a brilliant cut stone has the best facet angles for maximum brilliance. In fact the standard round brilliant cut consists of a total of 58 facets: 1 table, 8 bezel facets, 8 star facets and 16 lower-girdle facets, and usually a culet on the pavilion or base. The princess cut diamond is a square cut with lots of facets; it is a fairly modern cut but is very popular if you are looking for lots of sparkle in a more angular design.

There are many different types of fancy cuts, some which are very sparkly and others than have a low-key sparkle. This low-key sparkle is well known in jewellery of and inspired by the Art Deco period and with the cut being known a “stepped cut”. They are characterised by square or angled corners with rows of step like facets parallel to the table. There are several different shapes of step cuts such as; baguette, emerald and carré.

There are also other fancy cuts that have lots of sparkle such as: oval, pear, cushion, marquise and even heart shaped which all have a rounder softer look to them compared to the “stepped cuts”. However if you are looking for a diamond that has the classic shape of Art Deco period but would like extra sparkle there are a few interesting choices such as the Asscher cut which was invented in the Art Deco period it has a few extra facets so it has more a little extra sparkle than a stepped cut, the Radiant and scissor cut has the same shape as the emerald cut but over 70 facet for even more sparkle than the Asscher cut. There is also a very new cut that we have recently started using called a Korloff cut which is similar to the radiant and scissor cut as it has the classic emerald cut shape but it has 41 facets on the crown and 24 facets on the pavilion which gives it lots of brilliance.