Chrysocolla

Crysocolla is a sky blue, blue green, green colored hydrated copper silicate mineral with traces of oxides of copper, iron and manganese.
Chrysocolla usually occurs like a bright green or bluish crust, or as compact, grape-like groups. Crystals Intergrown with quartz or with opal tend to be more commonly utilized in jewellery.
The general structure of chrysocolla is botryoidal. It is associated with malachite, turquoise, jasper and quartz. Chrysocolla mixed with malachite and turquoise is known as eilat stone. Eilat stone is the best simulant for turquoise and sometimes can not be differentiated easily by visual observation. Chrysocolla mixed with jasper is known as parrot-wing which is of course very rare and sought by many jewelers. Chrysocolla mixed with quartz is known as stellarite which is pale blue in color.
Chrysocolla along with eilat stone, parrot wing and stellarite is extensively used in jewelries as beads, rings, ear rings, pendants, lockets, bracelets etc.
Copper-mining areas, particularly Chile, the first kind USSR, and Zaire. “Eilat Stone” (Intergrown with malachite and turquoise) reputedly originated from King Solomon’s mines.

Properties

Chemical Composition: 

Hydrated Copper Silicate - CuSiO₃.2H₂O

Classification / Type: 

-

Colors / Varieties: 

Sky blue, blue-green, green; with traces of oxides of Cu, Fe and Mn is brown-black, mixed with quartz matrix.

Crystal System / Forms: 

Crypto-crystalline aggregates with an enamel like texture.

Hardness: 

2 - 4; increases to 7 with more quartz mixtures.

Specific Gravity: 

2.00 - 2.45

Cleavage / Fracture: 

Nil.

Optic Character: 

Anisotropic (D.R.); Uniaxial positive / A.G.G.

Lustre: 

Greasy to vitreous.

Refractive Index / Birefringence: 

1.50 (mean R.I.)

Pleochroism: 

None.

Dispersion: 

None.

Magnification: 

Aggregate surface texture. Botryoidal.

U.V. Fluorescence: 

Variable

Spectrum: 

Not characteristic.

Cause of Color: 

Color varies with the impurity present. The blue color is due to the presence of copper.

Treatment (Enhancement): 

-

Specific Tests & Remarks: 

• Turns yellow with hydrochloric acid.
• Eilat stone: Chrysocolla mixed with malachite and turquoise.
• Parrot-wing: Chrysocolla mixed with jasper (brownish-green).
• Stellarite: Chrysocolla mixed with quartz has higher properties (light blue).

Synthesis: 

None.

Simulants (with key separation tests): 

Turquoise (R.I., S.G., spectrum, structure)

Geological Occurrence: 

Oxidized zones of copper deposits. May be mixed with copper carbonates such as malachite and turquoise.

Sources: 

U.S.A. (New Mexico), Russia, Chile, Peru and Zaire.

Cuts & Uses: 

Cabochon, beads, carvings, etc.