Chrysocolla

Chemistry: Hydrous copper silicate (variable).
Crystal system: Monoclinic; cryptocrystalline massive.
Color: Semi-translucent to opaque; green to blue; chrysocolla quartz; chrysocolla opal; Eilat stone: mixture of chrysocolla, turquoise, malachite and other copper minerals.
Hardness: 2 - 4
Cleavage: None; Fracture: even.
Specific gravity: 2.0 – 2.4; Eilat stone: 2.8 – 3.2
Refractive index: 1.50 approx; Eilat stone: 1.46 – 1.57 (varies with composition)
Luster: Vitreous.
Dispersion: -
Dichroism: -
Occurrence: Zone of weathering in copper lodes and deposits; Chile, DR Congo; Russia, USA, Peru, Australia.

Notes
Porous; R.I and heavy liquids can damage; may impregnate quartz/opal; color may be ‘mountain green, bluish green, sky blue, turquoise blue, often with an opal/enamel-like texture; Eilat stone found near Eilat, Gulf of Aquaba in Red Sea; mottled blue and green; contain copper carbonate malachite; reacts vigorously with acids; cut mainly cabochons.