Garnet is available in a veritable plethora of colours, such as yellow, orange, peach, green, red, purple, blue (rare), brown and pink. However, the most commonly occurring colour is red and the rarest is blue. Garnet also rarely occurs in colour-change varieties, which have a different colour depending on whether they are viewed in incandescent or natural light. The rarest colour-change garnet appears blue in daylight, and changes to purplish-red under torch light. Other colour-change garnets are green, beige, brown or grey in daylight, and change to reddish or purplish-pink under incandescent light. The colour of garnet is the most important quality factor.
Garnet Clarity and Lustre
Garnet exhibits a vitreous (glassy) lustre. The demantoid garnet, which is a green variety of andradite, has a high refractive index and is prized for its brilliance and adamantine (diamond-like) lustre. In fact, the name, “demantoid”, comes from the German word “demant”, meaning “diamond”, in reference to its lustre. Garnets are generally clean stones, however, almandine garnets sometimes have asbestos fibre inclusions. These inclusions cause asterism (a star effect), which is treasured due to its rarity. Additionally, some orange garnet, such as spessartite and hessonite tends to exhibit eye-visible inclusions. Andradite garnet is known for its distinctive, horsetail-like inclusions.
Garnet Cut and Shape
Garnets are extremely versatile and can be cut in any fashion and shape. Red garnet tends to be cut into standard shapes, whereas valuable garnets that are not often found in large sizes, such as tsavorite and demantoid, are cut into shapes that retain the most carat weight.
Garnet is not artificially enhanced in any way.