Spertiniite
{{infobox mineral
| name = Spertiniite
| boxwidth =
| image = Spertiniite-93262.jpg
| imagesize = 260px
| alt =
| caption = Spertiniite from Dzhezkazgan, Kazakhstan (size: 5 mm)
| category = Oxide mineral
| formula = Cu(OH)2
| IMAsymbol = Sni{{cite journal |last=Warr|first=L. N. |year=2021 |title=IMA–CNMNC approved mineral symbols |journal=Mineralogical Magazine |volume=85 |issue=3 |pages=291–320 |doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}
| 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
| twinning =
| cleavage = None
| fracture =
| tenacity = Brittle
| mohs = Soft
| luster = Vitreous
| streak =
| diaphaneity = Transparent
| gravity = 3.93
| density =
| polish =
| opticalprop = Biaxial
| refractive = nα = 1.720, nβ= n.d., nγ = > 1.800
| birefringence =
| pleochroism = Strong; X = colorless; Z = dark blue
| 2V =
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| other = Decomposes in hot water (synthetic)
| references = [https://.mindat.org/min-3724.html Spertiniite on Mindat][https://rruff.geo.arizona.edu/doclib/hom/spertiniite.pdf Spertiniite] in The Handbook of Mineralogy[https://webmineral.com/data/Spertiniite.shtml#.UFXq87IiZcg Spertiniite on Webmineral]
}}
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.[http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-12232.pdf 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][http://www.mindat.org/min-1040.html Chrysocolla on Mindat]
