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| Chalcanthite | |
|---|---|
 | |
| General | |
| Category | Sulfate mineral |
| Formula (repeating unit) | CuSO4·5H2O |
| IMA symbol | Cct[1] |
| Strunz classification | 7.CB.20 |
| Crystal system | Triclinic |
| Crystal class | Pinacoidal (1) (same H-M symbol) |
| Space group | P1 |
| Unit cell | a = 6.11 Å, b = 10.673 Å, c = 5.95 Å; α = 97.58°, β = 107.17°, γ = 77.55°; Z = 2 |
| Identification | |
| Color | Berlin blue to sky blue, greenish blue |
| Crystal habit | Typically stalactitic, encrusted, reniform or massive. Natural crystals are rare, but are short prismatic or tabular |
| Twinning | Rare as cruciform twins |
| Cleavage | Perfect on {110}; interrupted on {110} |
| Fracture | Conchoidal |
| Mohs scale hardness | 2.5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 2.12–2.3 |
| Optical properties | Biaxial (−) |
| Refractive index | nα = 1.514 nβ = 1.537 nγ = 1.543 |
| Birefringence | δ = 0.029 |
| 2V angle | Measured: 56° |
| Solubility | Soluble 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]
- ^ 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.
- ^ Chalcanthite Mineral Data, WebMineral.com
- ^ a b Chalcanthite, Mindat.org
- ^ Handbook of Mineralogy
- ^ Mindat Chalcanthite group