Shattuckite

Shattuckite is a copper silicate hydroxide mineral with formula Cu5(SiO3)4(OH)2. It crystallizes in the orthorhombic – dipyramidal crystal system and usually occurs in a granular massive form and also as fibrous acicular crystals. It is closely allied to plancheite in structure and appearance.

Shattuckite
General
CategoryInosilicate
Formula
(repeating unit)		Cu5(SiO3)4(OH)2
Strunz classification9.DB.40
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPcab
Identification
ColorDark and light blue, turquoise
Crystal habitCommonly spherulitic aggregates of acicular crystals
Cleavageperfect along [010] and [100]
Fractureuneven
Mohs scale hardness3.5
LusterDull to silky
StreakBlue
DiaphaneityTranslucent to opaque
Specific gravity4.1 (rather heavy for a non-metallic mineral)
Optical propertiesBiaxial (+)
Refractive indexnα = 1.753, nβ = 1.782, nγ = 1.815
PleochroismX = very pale blue; Y = pale blue; Z = deep blue
References[1][2][3]

Shattuckite is a relatively rare copper silicate mineral. It was first discovered in 1915 in the copper mines of Bisbee, Arizona, specifically the Shattuck Mine (hence the name). It is a secondary mineral that forms from the alteration of other secondary minerals. At the Shattuck Mine, it forms pseudomorphs after malachite. A pseudomorph is an atom by atom replacement of a crystal structure by another crystal structure, but with little alteration of the outward shape of the original crystal. It is sometimes used as a gemstone.[4]

  • Shattuckite with malachite, about 4 cm wide. Kaokoveld Mine, Namibia
  • Shattuckite crystals form concentric circular clusters of spraying, elongated, acicular crystals. Associated with them are small bits of contrasting primary malachite crystals in a deep green color
  • Botryoidal balls of shattuckite, from the Kaokoveld Mine, Kaokoveld Plateau, Kunene Region, Namibia
  • Polished shattuckite with malachite, New Cornelia mine, Ajo, Arizona. Size 5.3×5.1×5.0 cm

References
  1. Shattuckite. Webmineral.com. Retrieved on 2011-10-10.
  2. Shattuckite. Mindat.org (2011-09-08). Retrieved on 2011-10-10.
  3. Shattuckite. Handbook of Mineralogy. (PDF) . Retrieved on 2011-10-10.
  4. http://www.minerals.net/mineral/shattuckite.aspx
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