Caledonite

Infobox mineral
name = Caledonite
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caption =
formula = copper₂lead₅carbonate (sulfate)₃(hydroxide)₆
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color = Blue; Green
habit = typically prismatic or tabular; radial aggregates
system = Orthorhombic
twinning =
cleavage = [001] Perfect; [100] Distinct
fracture = Uneven
mohs = 2.5 - 3
luster = Vitreous
refractive = 1.81 - 1.90
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birefringence =
pleochroism = None
streak = Green-White; Blue-Green
gravity = 5.6 - 5.8
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diaphaneity = Transparent to translucent
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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.

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.

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:
*linarite, copperleadsulfatehydroxide₂
*malachite, copper₂(carbonate)(hydroxide)₂
*cerussite, leadcarbonate
*brochantite, copper₄(sulfate)(hydroxide)₆
*anglesite, leadsulfate

Alternative names

Caledonite has one major alterative name: caledonita.

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.

References

* [http://webmineral.com/data/Caledonite.shtml Webmineral Listing]
* [http://www.mindat.org/min-865.html MinDat Listing]
* [http://mineral.galleries.com/minerals/sulfates/caledoni/caledoni.htm Mineral Galleries]