Spertiniite
Spertiniite | |
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![]() Spertiniite from Dzhezkazgan, Kazakhstan (size: 5 mm) | |
General | |
Category | Oxide mineral |
Formula (repeating unit) | Cu(OH)2 |
Strunz classification | 4.FD.05 |
Dana classification | 6.2.4.1 |
Crystal system | Orthorhombic |
Crystal class | Pyramidal (mm2) H-M symbol: (mm2) |
Space group | Cmc21 |
Unit cell | a = 2.95 Å, b = 10.59 Å c = 5.27 Å; Z = 4 |
Identification | |
Formula mass | 97.56 g/mol |
Color | Blue, blue-green |
Crystal habit | Flat tabular crystals occurring in radial to botryoidal aggregates |
Cleavage | None |
Tenacity | Brittle |
Mohs scale hardness | Soft |
Luster | Vitreous |
Diaphaneity | Transparent |
Specific gravity | 3.93 |
Optical properties | Biaxial |
Refractive index | nα = 1.720, nβ= n.d., nγ = > 1.800 |
Pleochroism | Strong; X = colorless; Z = dark blue |
Other characteristics | Decomposes in hot water (synthetic) |
References | [1][2][3] |
Spertiniite is a rare copper hydroxide mineral. Chemically it is copper(II) hydroxide with formula Cu(OH)2. It occurs as blue to blue green tabular orthorhombic crystal aggregates in a secondary alkaline environment altering chalcosite. Associated minerals include chalcocite, atacamite, native copper, diopside, grossular and vesuvianite.[2]
Discovery and occurrence
It was first described in 1981 for an occurrence in the Jeffrey quarry of the Johns-Manville mine, Asbestos, Estrie, Québec. It was named for mine geologist Francesco Spertini (born 1937).[1][2] In addition to the type locality, it has also been reported from Mont Saint-Hilaire, Quebec; Ely, White Pine County, Nevada; and Bisbee, Cochise County, Arizona. It has been reported from Dzhezkazgan, Kazakhstan; from slag at Juliushutte, Astfeld, Harz Mountains, Germany; and from Tsumeb, Namibia.[2]
A 2006 study has produced evidence the blue mineral chrysocolla may be a microscopic mixture of spertiniite, amorphous silica and water.[4][5]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/79/Kristallstruktur_Kupfer%28II%29-hydroxid.png/220px-Kristallstruktur_Kupfer%28II%29-hydroxid.png)
References
- ^ a b Spertiniite on Mindat
- ^ a b c d Spertiniite in the Handbook of Mineralogy
- ^ Spertiniite on Webmineral
- ^ François Farges, Karim Benzerara, Gordon E. Brown, Jr.; Chrysocolla Redefined as Spertiniite; SLAC-PUB-12232; 13th International Conference On X-Ray Absorption Fine Structure (XAFS13); July 9-14, 2006; Stanford, California
- ^ Chrysocolla on Mindat