Chlorocalcite
A rare potassium-calcium chloride found in active volcanic fumaroles — described from Vesuvius in 1872, before anyone knew it contained potassium.
Intro adapted from Wikipedia (CC BY-SA).
Chlorocalcite is an IMA-recognized mineral species in the halide class, with the chemical formula KCaCl₃.
Key properties: Mohs hardness 2.5–3; specific gravity 2.16; optically biaxial.
IMA symbol Ccal, grandfathered status — known before the IMA’s founding, named in 1872.
Found as a sublimate in volcanic fumaroles (Vesuvius, Italy).
It is found associated with Sylvite, halite, hematite (Vesuvius, Italy); halite, tachyhydrite (Stassfurt, Germany).
The name refers to CHLORine and CALCium in the composition.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data and a Wikipedia introduction — a full written entry hasn’t been published yet.
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