“Mark's Tree Frog Carving,” hand-carved chrysoprase, by Jessa and Mark Anderson. Licensed under CC By 2.0.
Chrysoprase is apple-green chalcedony that derives its color from nickel. Its hardness and striking color make it a popular gemstone for jewelry as well as carvings.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
| Cabochons | All sizes |
| to /ct |
| Data | Value |
|---|---|
| Name | Chrysoprase |
| Is a Variety of | Chalcedony |
| Crystallography | Hexagonal, microcrystalline. |
| Refractive Index | 1.540-1.553 |
| Colors | Green, from olive to apple and pure shades. |
| Luster | Greasy, waxy. |
| Hardness | 6.5 - 7 |
| Wearability | Very Good |
| Fracture | Conchoidal, granular |
| Specific Gravity | 2.651-2.91 |
| Birefringence | 0.004-0.009 |
| Cleavage | None |
| Dispersion | None. |
| Transparency | Nearly opaque to nearly transparent. |
| Pleochroism | None. |
| Optics | o = 1.540; e = 1.553. Uniaxial (+). |
| Optic Sign | Uniaxial + |
| Etymology | From the Greek chrysos, “golden,” and prase, “leek,” alluding to its green color. |
Chrysoprase (Quartz): Australia (largest beads ~ 8 mm). Photo © Joel E. Arem, PhD, FGA. Used with permission.
A variety of chalcedony, chrysoprase is a cryptocrystalline quartz gemstone. Transparency ranges from nearly opaque to nearly transparent. Its colors range from apple to olive green and nearly pure greens with medium tones.
While some chalcedony varieties, such as “mtorolite” from Zimbabwe, may derive their green color from chromium, chrysoprases get their color from nickel.
Sometimes, the term “prase” is used to described chrysoprase gems with darker tones. However, prase is also used to refer to green chalcedonies colored by chlorite inclusions found in Europe.
Very fine, highly saturated chrysoprase gems have been misidentified as “Imperial jade.”
“Quartz Var. Chrysoprase,” Marlborough, Rockhampton Region, Queensland, Australia. © Rob Lavinsky, www.iRocks.com. Used with permission.
Chalcedonies may be dyed green to simulate these stones.
Most chrysoprase sold today comes from Australia.
“Chrysoprase – Brazil” by Stephanie Clifford. Licensed under CC By 2.0.
Locations near Kalgoorlie, Western Australia have yielded 700 and 1,470 kg nodules.
Chrysoprase jewelry may fade if exposed to sunlight or heat. The color may return if stored with moisture (such as soft cotton moistened with water). (Editor’s Note: contributor and jewelry maker Howard Denghausen writes that only dyed chrysoprases will fade in sunlight).
This gemstone requires no special care. A combination of mild detergent, warm water, and a soft brush is a good choice for cleaning. Consult our gemstone jewelry cleaning guide for more recommendations.
“Ring with Chrysoprase” by Strangell. Licensed under CC By-SA 2.0.
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