Chrysoprase
Chrysoprase is the green chalcedony that most often gets mistaken, at a glance, for jade — an understandable mix-up, since both share a similar translucent, apple-to-mint green, but the two are entirely different minerals with different chemistry, hardness, and market value. Chrysoprase’s color comes specifically from trace nickel worked into the chalcedony’s silica structure, a distinct coloring mechanism from the iron oxide behind carnelian and sard or the manganese behind amethyst, and it’s this nickel content that defines chrysoprase as its own named variety rather than just “green chalcedony.”
Species and variety. Chrysoprase is a variety of chalcedony, the cryptocrystalline (fine-grained, fibrous) form of quartz, chemically SiO2 like every other chalcedony variety on this site. What separates chrysoprase from agate, carnelian, or plain gray chalcedony is purely the nickel-driven color; the underlying silica structure is identical.
Appearance and color range. The classic chrysoprase color is a bright, slightly yellowish apple-green, though material can range toward a deeper, more saturated green or a paler, more yellow-green depending on nickel content and locality. The finest material is translucent with even, vivid color and no visible mottling; cloudier or unevenly colored material is common and worth considerably less.
Hardness and everyday care. At roughly 6.5–7 on the Mohs scale, chrysoprase wears well in everyday rings, bracelets, and pendants, resisting scratches from normal contact. As with other chalcedony varieties, it is more vulnerable to chipping from sharp impacts than to scratching, so it is best stored apart from harder stones and cleaned with mild soap and water.
Where it is found. Australia is the best-known modern source of fine chrysoprase, alongside historic production from Poland (long associated with the material historically) and additional sources in Brazil, the United States, and Kazakhstan.
Birthstone role. Chrysoprase is a May birthstone only in the UK 2013 system, listed as an alternative alongside emerald — the historical, US 1912, and US current systems all give May to emerald alone. It does not appear in any of the zodiac systems tracked on this site.
Gemmological properties
| Mohs hardness | 6.5–7 |
|---|---|
| Crystal system | Trigonal (cryptocrystalline) |
| Chemical formula | SiO2 |
| Refractive index | 1.53–1.54 |
| Color family | Green |
| Variety of | chalcedony |
| Also known as | — |
| Origins | Australia, Poland, Brazil, United States, Kazakhstan |
| Organic material | No |
Chrysoprase's apple-green color comes from trace nickel, distinguishing it from other chalcedony varieties colored by iron or other inclusions.
Where Chrysoprase appears as a birthstone
By month
| Month | System | Confidence |
|---|---|---|
| May | UK 2013 | high |
Frequently asked questions
- What makes chrysoprase green, if it's the same silica as clear quartz?
- Trace nickel distributed through the chalcedony's microstructure produces chrysoprase's apple-green color — a different coloring mechanism from the iron oxide behind carnelian and sard, or the manganese behind amethyst. Nickel is what specifically defines chrysoprase among the many colors chalcedony can take.
- Is chrysoprase valuable compared to emerald, since both are green and both are a May stone in the UK?
- No — despite sharing a birthstone month in one system, they are unrelated materials at very different price points. Chrysoprase is a comparatively affordable, opaque-to-translucent chalcedony; emerald is a rare, usually much more expensive, transparent beryl. The UK 2013 list pairs them as alternatives, not equivalents.