Star K 7mm Round Created Blue Opal Pendant Sterling Silver

Cut

A gemstone's cut refers to its proportions and symmetry. In making a gemstone look appealing--the stone should be symmetrical in all dimensions so that it will appear balanced, and that its facets will reflect light evenly. Color should also be taken into account when cutting for optical efficiency. If a stone's color is highly saturated, a shallow cut will allow it to pass more light, while a deeper cut may increase the vividness of a less saturated gem. There is no generally accepted grading system for gemstone cut.

Size

Though a gemstone's weight is usually given in carats, this may not give an accurate idea of its size, because different types of stone have different densities. Therefore, a one-carat sapphire or ruby will be smaller than a one-carat emerald, though they have the same weight, because sapphires and rubies (both a form of the mineral corundum) are more dense than emeralds.

Gemstones can also be measured in dimensions (diameter, length, and width). It is important to know the dimensions to ensure that the gemstone weight will be visible and well-proportioned in the setting.