Spertiniite

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Spertiniite
Spertiniite-93262.jpg
Spertiniite from Dzhezkazgan, Kazakhstan (size: 5 mm)
General
Category Oxide mineral
Formula Cu(OH)2
IMA symbol Sni [1]
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
ColorBlue, blue-green
Crystal habit Flat tabular crystals occurring in radial to botryoidal aggregates
Cleavage None
Tenacity Brittle
Mohs scale hardnessSoft
Luster Vitreous
Diaphaneity Transparent
Specific gravity 3.93
Optical propertiesBiaxial
Refractive index nα = 1.720, nβ= n.d., nγ = > 1.800
Pleochroism Strong; X = colorless; Z = dark blue
Other characteristicsDecomposes 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]

Discovery and occurrence

It was first described in 1981 for an occurrence in the Jeffrey Mine of the Johns-Manville mine, Val-des-Sources, Quebec. 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]

Crystal structure of spertiniite Kristallstruktur Kupfer(II)-hydroxid.png
Crystal structure of spertiniite

References

  1. 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.
  2. 1 2 Spertiniite on Mindat
  3. 1 2 3 4 Spertiniite in The Handbook of Mineralogy
  4. Spertiniite on Webmineral
  5. 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
  6. Chrysocolla on Mindat