Chrysoprase

Overview

Chrysoprase is the most valuable variety of chalcedony, a compact form of quartz made of microscopic crystals. Its fresh apple-green colour comes from tiny particles of nickel-bearing minerals. It is usually cut as cabochons, beads and carvings, where its smooth, glowing translucency shows best.

Colour

The finest chrysoprase is an even, intense apple green with good translucency and no veins or brown spots. Paler, minty stones are more affordable. Very translucent, saturated material from Queensland, Australia, is regarded as the benchmark.

Key properties

Where chrysoprase comes from

Australia (Queensland and Western Australia) is the leading source today. Tanzania, Brazil, Kazakhstan and the United States also produce it, and Poland was the classic European source, used in palaces and churches in the 18th century.

Treatments and imitations

Natural chrysoprase is usually untreated. The main concern is dyed green chalcedony or agate sold as chrysoprase; dyed stones often show colour concentrated in cracks or uneven banding. Ask for any treatment to be disclosed, and buy from sellers who stand behind their descriptions.

Buying tips

• Look for even, saturated colour and good translucency when held to the light.
• Avoid stones with brown matrix or veins unless you like the natural look.
• Mind the setting: chrysoprase is tough enough for rings worn with care, but pendants and earrings keep it safer.

Care and cleaning

Clean with warm soapy water and a soft brush, then dry. Avoid ultrasonic and steam cleaners, heat and harsh chemicals. Do not leave chrysoprase in strong sunlight or near heat for long: it can lose water and fade. Many collectors store it away from light, wrapped in a soft cloth.