Chrysoprase Identification Guide

What Chrysoprase Looks Like

Chrysoprase is the apple-green to nickel-green variety of chalcedony (microcrystalline quartz), colored by nickel. Its hue ranges from a fresh, almost mint apple-green to a deeper grass-green; the best material is even and translucent. Luster is waxy to vitreous, and it is translucent to opaque with no visible crystals — it has the smooth, uniform look typical of chalcedony. It usually occurs as nodules, veins, and crusts in weathered nickel-bearing rock.

Step-by-Step Field ID Checklist

1. Note the color. A bright, slightly yellowish "apple" green that is evenly distributed (not banded like agate).
2. Check luster and texture. Waxy/greasy luster, smooth conchoidal surfaces, translucent edges.
3. Test hardness. Mohs 6.5-7 (true quartz hardness) — scratches glass and steel.
4. Look for fracture. Conchoidal, glassy fracture; no cleavage.
5. Hold to light. Even translucency without the fibrous shimmer of jade.
6. Check for fading clues. Heat/strong sunlight can dull some chrysoprase—handle accordingly.

Key Diagnostic Tests

• Hardness: 6.5-7.
• Cleavage: None; conchoidal fracture.
• Streak: White.
• Density: ~2.58-2.64 g/cm3 (quartz range).
• Acid: Inert (no fizz).
• Magnetism: None.
• Optics: Aggregate; faint to no reaction under standard gem filters; nickel coloring (not chromium) means no red Chelsea-filter reaction.

Common Look-Alikes and How to Tell Them Apart

• Jade (jadeite/nephrite): Jade is tougher with a fibrous/interlocking texture and slightly different feel; nephrite is softer (6-6.5) and jadeite denser (~3.3). Chrysoprase has quartz hardness and density (~2.6) and a more uniform, glassy green.
• Green aventurine: Aventurine shows glittery mica/fuchsite inclusions (aventurescence); chrysoprase is clean and even.
• Dyed green chalcedony / dyed agate: Dye often concentrates in fractures or looks too uniform; chrysoprase color is natural and nickel-based. Magnification may reveal dye in cracks.
• Variscite / green opal: Opal is softer (5.5-6.5) and lower density; variscite is a phosphate, softer.
• Chrome chalcedony (mtorolite): Colored by chromium (reacts red under Chelsea filter), unlike nickel-colored chrysoprase.

Where It Is Typically Found

Chrysoprase forms where nickel-bearing rocks (serpentinites, laterites) weather and silica-rich fluids deposit chalcedony in cracks and cavities. The most famous modern source is Marlborough and Yerilla, Queensland and Western Australia. Historic and additional sources include Poland/Czech region (Silesia, the classic European source), Tanzania, Brazil, Kazakhstan, and the United States (California, Arizona).

Field Tips and Common Mistakes

The single most useful check is uniformity: genuine chrysoprase has an even, slightly translucent apple-green throughout, while dyed green agate or chalcedony shows color pooling in cracks and a too-perfect, sometimes "electric" green; magnify and look for dye concentrating along fractures. Confirm quartz hardness (6.5-7) by scratching glass, which rules out softer green opal and variscite. The Chelsea-filter trick separates the two natural green chalcedonies: chrysoprase (nickel) stays inert, whereas chrome chalcedony (mtorolite) glows red. Beware buying in hot, bright shop windows—some chrysoprase pales under prolonged heat and strong light and may partly recover in storage, so judge color in neutral light. When distinguishing from jade, look at break surfaces: chrysoprase breaks with a clean glassy conchoidal fracture, while jade resists breaking and shows a splintery, fibrous toughness. Tumbled chrysoprase often retains a slightly waxy luster that helps separate it from glassier faceted quartz.