Whitecapsite
Whitecapsite is an IMA-recognized mineral species in the arsenate class, with the chemical formula H₁₆Fe²⁺₅Fe³⁺₁₄Sb³⁺₆(AsO₄)₁₈O₁₆·120H₂O.
It crystallizes in the hexagonal crystal system (space group P6_3/m).
Key properties: Mohs hardness 2–2.5; specific gravity 2.3; Yellow streak; Strongly vitreous luster; optically uniaxial.
IMA symbol Wcp, IMA status: approved, named in 2012.
Found as a secondary mineral in the oxidation zone of a hydrothermal sulfide deposit containing arsenopyrite, pyrite and stibnite.
It is found associated with Picropharmacolite, guerinite, sulfur, gypsum; or metastibnite, jarosite, goethite, pitticite, gypsum, picropharmacolite.
The name refers to the locality from which the first specimens were obtained.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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