How to Choose a Diamond Cut (Polish, Symmetry, and Proportion)

Perhaps the first step is to determine the size and shape of the diamond ring when it is still in its rough stage. Not every rough diamond can give a good set of proportioned diamond. The cutter usually tries to balance the proportions while maintaining the weight. The cutter will also have to keep in mind popular shapes which would be marketable.

The cut of the diamond is not necessarily the same as the shape of the diamond for your ring. The style can be distinguished between the girdle outline which would be the external shape of the diamond. The cut is the faceting of the diamond which can be distinguished by looking inside the diamond. The cut can actually determine the amount of light that could go through the diamond, making it more brilliant or less for that matter. Example cuts could include brilliant cut, step cut or a mix of both.

Other proportions that affects how one determines the cut can be seen through diamond are based on mainly two things:

• the proportions relating to the girdle thickness, table size, crown height, pavilion depth, crown angle, and pavilion angle
• one of the tips that most jewelers give is to try and maintain the proportions close to each other to make the diamond look nicer.

The set of proportions however, is not a set mark. Because there is a lot of differentiating grading systems, the cut grading is dependent of the jeweler. Eventually, the price is reflected in the end if the diamond has a better cut but lesser weight costing more per carat.

It is also important to remember that a diamond's proportions are often determined by the size and shape of the diamond rough. When we consider diamond cutting theoretically, it is easy to assume that any piece of rough can yield well-proportioned diamonds. In the real world, however, this is not always the case. A cutter often has to balance aversions (e.g., removing or minimizing the effects of inclusions) with desired (e.g., creating well-cut proportions and retaining weight from the rough) when faceting a diamond from a piece of rough diamond. Cutters also have to consider what shapes and proportions will readily sell in the market. Among desirable outcomes, cutters continually have to decide whether to cut a better-proportioned diamond, or retain more weight from the rough. Often, those diamonds that are considered well cut retain less original weight in order to achieve their proportions, and therefore cost more per carat to manufacture. This price difference is usually passed on to the consumer, which is why cut has become another important choice to consider when purchasing diamonds.

These are guidelines used for quality purposed of the cut. Lesser proportions and symmetry are usually accepted among the cutters to avoid inclusions or to maintain the carat quality. Polishing and cutting of the diamond can cause up to more than 50% loss of diamond weight. That is why sometimes, jewelers recommend buying a lesser carat because of the better quality cut rather than a 1.10 carat. In the end, the polishing will determine the clarity of the surface as the symmetry assesses evenness of the shape and the facets of the diamond.