Chalcanthite

Chalcanthite
General
CategorySulfate mineral
Formula
(repeating unit)
CuSO4·5H2O
IMA symbolCct[1]
Strunz classification7.CB.20
Crystal systemTriclinic
Crystal classPinacoidal (1)
(same H-M symbol)
Space groupP1
Unit cella = 6.11 Å, b = 10.673 Å,
c = 5.95 Å; α = 97.58°,
β = 107.17°, γ = 77.55°; Z = 2
Identification
ColorBerlin blue to sky blue, greenish blue
Crystal habitTypically stalactitic, encrusted, reniform or massive. Natural crystals are rare, but are short prismatic or tabular
TwinningRare as cruciform twins
CleavagePerfect on {110}; interrupted on {110}
FractureConchoidal
Mohs scale hardness2.5
LusterVitreous
StreakWhite
DiaphaneityTransparent to translucent
Specific gravity2.12–2.3
Optical propertiesBiaxial (−)
Refractive indexnα = 1.514 nβ = 1.537 nγ = 1.543
Birefringenceδ = 0.029
2V angleMeasured: 56°
SolubilitySoluble in water, turning it blue
Other characteristics Poisonous
References[2][3][4]

Chalcanthite (from Ancient Greek χάλκανθον (khálkanthon), from χαλκός (khalkós) 'copper' and ἄνθος (ánthos) 'flower, bloom') is a richly colored blue-green water-soluble sulfate mineral CuSO4·5H2O. It is commonly found in the late-stage oxidation zones of copper deposits. Due to its ready solubility, chalcanthite is more common in arid regions.

Chalcanthite is a pentahydrate and the most common member of a group of similar hydrated sulfates, the chalcanthite group. These other sulfates are identical in chemical composition to chalcanthite, with the exception of replacement of the copper ion by either manganese as jokokuite, iron as melanterite, or magnesium as pentahydrite.[5]

Other names include blue stone, blue vitriol, and copper vitriol.[3]

  1. ^ Warr, L. N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. Vol. 85, no. 3. pp. 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Chalcanthite Mineral Data, WebMineral.com
  3. ^ a b Chalcanthite, Mindat.org
  4. ^ Handbook of Mineralogy
  5. ^ Mindat Chalcanthite group