Chlorocalcite is a rare potassium calcium chloride evaporite mineral with formula: KCaCl3. It is found in active volcanic fumaroles.

Chlorocalcite
General
CategoryHalide mineral
Formula
(repeating unit)
KCaCl3
IMA symbolCcal[1]
Strunz classification3.AA.40
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPnma (from synthetic crystals)
Unit cella = 7.35 Å, b = 10.44 Å,
c = 7.25 Å; Z = 4
Identification
Formula mass185.54 g/mol
ColorWhite, tinged violet
Crystal habitPrismatic or tabular cube-like crystals, pseudo cubic
CleavagePerfect on {001}, good on {010} and {100}
Mohs scale hardness2.5-3
DiaphaneityTransparent to semi-transparent
Density2.16 calculated
Optical propertiesBiaxial (–)
Refractive index~1.52
Birefringenceweak
SolubilityIn water
Other characteristicsDeliquescent
References[2][3][4][5]

It was first described in 1872 for an occurrence on Mount Vesuvius and given the name for its calcium content previous to discovering that it also contained potassium.[3][4] It has also been reported from the Desdemona Mine, Peine, Lower Saxony, Germany.[3]

References

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  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. ^ Mineralienatlas
  3. ^ a b c Chlorocalcite on Mindat.org
  4. ^ a b Chlorocalcite on Webmineral
  5. ^ Handbook of Mineralogy