Diamond Cutting is the art, skill and, increasingly, science of changing a diamond from a rough stone into an attractive gem. It is possible only because the hardness of diamond varies widely according to the direction one is trying to cut or grind.

'Cut' has two meanings in relation to diamonds. The first is the shape, round, oval and such. The second relates to the specific quality of cut within the shape and the quality and price will vary very greatly based on the cut quality.

The price of a diamond is affected by:

  • the weight
  • the color. More clear, commonly called white, is generally of greater value for diamonds which do not have strong color. For a diamond with a strong color it may be a 'fancy' color and the value can sometimes be greater than a white diamond if the color is rare.
  • the shape (cut). Round brilliant cut diamonds generally have the highest price for a given weight. This advantage is somewhat offset, for a cutter, by the tendency to lose more weight when cutting them.
  • the presence of imperfections, most commonly inclusions within the body of the diamond or imperfections left on the surface.

For all shapes ('cuts') of diamond, the cutter has two objectives which often conflict: to preserve the geatest possible amount of the weight of the rough diamond and to produce a cut which is both attractive and highly valued by the marketplace. The initial step is to choose the shapes of the final diamonds which will be produced from a particular piece of rough. This can be a very complicated choice, since it can involve tradeoffs to avoid inclusions (is more weight with this inclusion more or less valuable than lower weight without it?) or areas of less valuable color.

Round brilliant

Round brilliant diamonds are the round shaped diamonds commonly used in the typical engagement ring. In this category there is, in many markets, growing appreciation of the importance of a good or excellent cut, for a diamond with more weight but a less good cut can be both more costly and less attractive. As a result, diamonds of good cut command a price premium if you work out the price per carat. Ideal and super-ideal cut diamonds command these price premiums.