| Spertiniite | |
|---|---|
 Spertiniite from Dzhezkazgan, Kazakhstan (size: 5 mm) | |
| General | |
| Category | Oxide mineral |
| Formula (repeating unit) | Cu(OH)2 |
| IMA symbol | Sni |
| 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 | |
Spertiniite is a rare copper hydroxide mineral. Chemically, it is copper(II) hydroxide with the formula Cu(OH)2. It occurs as blue to blue-green tabular orthorhombic crystal aggregates in a secondary alkaline environment altering chalcocite. Associated minerals include chalcocite, atacamite, native copper, diopside, grossular, and vesuvianite.
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). 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.
A 2006 study has produced evidence the blue mineral chrysocolla may be a microscopic mixture of spertiniite, amorphous silica and water.
-hydroxid.png)
References
- Warr, L. N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Spertiniite on Mindat
- ^ 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