Caledonite

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Caledonite
Category Mineral
Chemical formula Cu2Pb5CO3(SO4)3(OH)6
Identification
Color Blue; Green
Crystal habit typically prismatic or tabular; radial aggregates
Crystal system Orthorhombic
Cleavage [001] Perfect; [100] Distinct
Fracture Uneven
Mohs Scale hardness 2.5 - 3
Luster Vitreous
Refractive index 1.81 - 1.90
Pleochroism None
Streak Green-White; Blue-Green
Specific gravity 5.6 - 5.8
Diaphaneity Transparent to translucent

Caledonite, whose name derives from Caledonia, the historical name of its place of discovery (Scotland), is a richly colored blue-green sulfate mineral with an orthorhombic crystal structure, commonly found in the oxidized zones of copper-lead deposits as a secondary mineral.

Contents

[edit] Uses of caledonite

Caledonite is a very minor ore mineral of lead and copper, but its rarity makes its industrial use limited. Due to its occasionally striking crystals and vibrant color, however, caledonite has value as a collector's mineral.

[edit] Associated minerals

Given that caledonite is found in oxidized copper/lead deposits, it is frequently found in association with other copper and lead minerals. Frequently associated minerals include:

[edit] Alternative names

Caledonite has one major alterative name: caledonita.

[edit] Notes for identification

Caledonite's blue color is a useful indicator, but insufficient, especially since one of its associates, linarite, is a vivid blue as well. Useful tests for determining if a specimen is caledonite include its density, streak, and crystal habit.

[edit] References