| Spertiniite | |
| Category: | Oxide mineral |
| Formula: | Cu(OH)2 |
| Imasymbol: | Sni[1] |
| Molweight: | 97.56 g/mol |
| Strunz: | 4.FD.05 |
| Dana: | 6.2.4.1 |
| System: | Orthorhombic |
| Class: | Pyramidal (mm2) H-M symbol: (mm2) |
| Symmetry: | Cmc21 |
| Unit Cell: | a = 2.95 Å, b = 10.59 Å c = 5.27 Å; Z = 4 |
| Color: | Blue, blue-green |
| Habit: | Flat tabular crystals occurring in radial to botryoidal aggregates |
| Cleavage: | None |
| Tenacity: | Brittle |
| Mohs: | Soft |
| Luster: | Vitreous |
| Diaphaneity: | Transparent |
| Gravity: | 3.93 |
| Opticalprop: | Biaxial |
| Refractive: | nα = 1.720, nβ= n.d., nγ = > 1.800 |
| Pleochroism: | Strong; X = colorless; Z = dark blue |
| Other: | Decomposes in hot water (synthetic) |
| References: | [2] [3] [4] |
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.[3]
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).[2] [3] 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.[3]
A 2006 study has produced evidence the blue mineral chrysocolla may be a microscopic mixture of spertiniite, amorphous silica and water.[5] [6]