Stunning green hues and a brilliance that outshines diamond combine to make demantoids truly captivating. This variety of garnet is an entirely different stone than the more familiar dark red gems of the garnet family. In fact, demantoid garnets are much rarer than the red varieties and are the most valuable type. Although named demantoid, or “diamond-like,” these garnets actually exceed diamonds in both brilliance and dispersion. Their horsetail inclusions are a delight to collectors, too.

Before your next demantoid garnet buying trip, read up on what makes this variety of the January birthstone unique and the quality factors that most impact cost.

Demantoid Garnet Buying and the Four Cs

The IGS garnet value listing has price guidelines for demantoid garnet. Learn to identify the different species of garnet.

Color

Demantoid is the green variety of andradite garnet, with colors ranging from deep forest greens to light, nearly colorless hues. For this variety, the connoisseur’s most important consideration is the trade-off between depth of color and visible brilliance.

While demantoid has a higher dispersion than diamond, darker tones may obscure this effect. Still, medium-dark tones hold the highest value, where the green color is strongest. For those…