Chrysocolla

About it

Soft sky-blue to green crusts and masses where copper ores weather, often sticking to the tongue; quartz-hardened "gem silica" from Arizona and Peru is cut as a gem.

Type

Mineral

Group

Silicate (phyllosilicate)

Formula

(Cu,Al)2H2Si2O5(OH)4·nH2O

Hardness (Mohs)

2–4

Specific gravity

1.9–2.4

Streak

white to pale blue

Lustre

vitreous (glassy), waxy, earthy

Crystal system

Orthorhombic

Colours

blue, blue-green, green, turquoise

Transparency

transparent, translucent, opaque

Cleavage and fracture

none; conchoidal to uneven fracture

Typical values: real specimens vary. For more, see mindat.org.