Judging quality
Gem silica shows translucent turquoise blue with a hard glassy polish; plain chrysocolla is chalky and easily marked with a fingernail. Peruvian material combines it with malachite and cuprite.
Silicate
Chrysocolla
A soft, hydrated copper silicate in vivid blue-green. On its own it is too fragile to work, so gem material is usually chrysocolla in chalcedony, called gem silica.
Care
Very soft and porous unless silicified. Keep dry and away from oils.
History & lore
The name comes from Greek for 'gold glue' — it was used as a flux in soldering gold.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Chrysocolla
- What is Chrysocolla?
- A soft, hydrated copper silicate in vivid blue-green. On its own it is too fragile to work, so gem material is usually chrysocolla in chalcedony, called gem silica.
- How hard is Chrysocolla and what is it made of?
- Chrysocolla is a Silicate-family mineral with the composition (Cu,Al)2H2Si2O5(OH)4·nH2O. It crystallizes in the orthorhombic system and rates 2-4 on the Mohs hardness scale. It occurs in blue-green, cyan.
- Where does Chrysocolla come from?
- Notable localities for Chrysocolla include Peru, DR Congo, USA (Arizona), Israel (Eilat).
- How do you tell good Chrysocolla from filler?
- Gem silica shows translucent turquoise blue with a hard glassy polish; plain chrysocolla is chalky and easily marked with a fingernail. Peruvian material combines it with malachite and cuprite.
- How do you care for Chrysocolla?
- Very soft and porous unless silicified. Keep dry and away from oils.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.