Chrysoprase Buying Guide

Chrysoprase Buying and the Four Cs

The IGS chrysoprase value listing has price guidelines for cabochons.

Color

Chrysoprase is a green variety of chalcedony, a non-crystalline quartz. Colored by tiny inclusions of pimelite, this is a rare example of a green gem whose color arises from nickel. Chromium, which imparts a green hue in emerald, can also create green chalcedony. However, this chrome chalcedony constitutes a distinct gem variety from chrysoprase.

Gemologists describe color using hue, tone, and saturation. For chrysoprase, the primary hue is green, and top-color gems are a bright, apple green. Secondary hues of yellow or blue may be present. However, secondary yellow hues are undesirable. Top-quality specimens won’t show these. Slight blue hues are more preferable. Some chrysoprase may even be blue-green or aqua in color.

In chrysoprase, medium to medium-dark tones are ideal. This allows for a brightly saturated gem. Lighter tones can appear washed-out, and darker tones never reach the saturation of a medium-toned specimen. Sometimes, darker-toned chrysoprase is referred to as “prase.”

Clarity and Transparency

Because of the material’s abundance, chrysoprase should have excellent clarity. Thus, inclusions shouldn’t be visible to the eye. However, dendritic …