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Tyrolite

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Tyrolite
General
CategoryArsenate and carbonate minerals
Formula
(repeating unit)
CaCu5(AsO4)2CO3(OH)4·6H2O
IMA symbolTyl[1]
Strunz classification8.DM.10
Crystal systemOrthorhombic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP2/c (no. 13) or C2/c (no. 15)
Identification
ColorBlue to green
Crystal habitRadial or botryoidal
Mohs scale hardness1.5–2.0
LusterVitreous
DiaphaneityTranslucent
Specific gravity3.1–3.2
Refractive indexnα = 1.694
nβ = 1.726
nγ = 1.730
References[2]

Tyrolite is a hydrous calcium copper arsenate carbonate mineral with the formula CaCu5(AsO4)2CO3(OH)4⋅6H2O. Tyrolite forms glassy, blue to green orthorhombic radial crystals and botryoidal masses. It has a Mohs hardness of 1.5–2.0 and a specific gravity of 3.1–3.2. It is translucent with refractive indices of nα = 1.694, nβ = 1.726, and nγ = 1.730.

It is a secondary mineral formed by the weathering of associated copper and arsenic minerals. It was first described in 1845 for an occurrence in Schwaz, Tyrol, Austria.

Chrysocolla on tyrolite and clinotyrolite specimen (4.0 cm × 2.6 cm × 2.6 cm (1.6 in × 1.0 in × 1.0 in)); from San Simon Mine in Santa Rosa-Huantajaya District, Iquique Province, Chile.
(Click image for details of the mineral chemistry.)

References

[edit]
  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. ^ Krivovichev, S. V. (1 August 2006). "Crystal chemistry and polytypism of tyrolite". American Mineralogist. 91 (8–9): 1378–1384. Bibcode:2006AmMin..91.1378K. doi:10.2138/am.2006.2040. S2CID 96895661.