The
colour (or the lack of it) is one of the main characteristics of gemstones and perhaps the most important.
The
clarity is another important characteristics when evaluating gemstones.
The
cut is also of great importance. Generally there are two types of cuts —
commercial and
precision. The main objective in first one is to preserve as much as possible of the crystal’s size, respectively weight, while the second follows exact proportions, angles, etc., always in relation with the specific mineral that is faceted.
In addition to the above 3 in the evaluation of gemstones an important role plays the size/weight (measured in carats; 1 carat = 200 milligrams).