Crystal Chrysocolla

Chemical Formula

Cu₂H₂Si₂O₅(OH)₄
 

Composition

Basic copper silicate, often with some aluminum. The composition of this mineral is usually variable and it therefore lacks a definitive chemical composition.
 

Variable Formula

(Cu_2-x,Al_x)H_2-xSi₂O₅(OH)₄ · nH₂O

Color

Bright green, bluish-green, sky blue, gray. May be mottled or multicolored green and blue.

Streak

White to pale blue

Hardness

2 - 4

Crystal System

Orthorhombic

Crystal Forms 
and Aggregates

Chrysocolla is never in visible crystals. It is almost always in botryoidal, reniform, or stalactitic groups, in rounded balls, and in massive form. Also in solid and fibrous veins, in tufts of fibrous crystals, and in crusts. Frequently forms pseudomorph after other minerals, especially Azurite.
 

Transparency

Translucent to Opaque

Specific Gravity

2.0 - 2.2

Luster

Vitreous to greasy

Cleavage

None

Fracture

Conchoidal to uneven

Tenacity

Brittle

In Group

Silicates; Phyllosilicates

Striking Features

Bright color, hardness, and habits

Environment

As a secondary alteration mineral in the oxidation zone of copper deposits, hydrothermal replacement deposits, and in igneous rocks.
 

Rock Type

Igneous, Sedimentary, Metamorphic

Popularity (1-4)

2

Prevalence (1-3)

2

Demand (1-3)

2