Tags: Chemical Substance, Mineral.
Picropharmacolite Ca4Mg(AsO3OH)2(AsO4)2·11H2O is a rare arsenate mineral. It was named in 1819 from the Greek for bitter in allusion to its magnesium content and its chemical similarity to pharmacolite. The mineral irhtemite Ca4Mg(AsO3OH)2(AsO4)2·4H2O has the same composition as picropharmacolite except that it has only four water molecules per formula unit instead of eleven. It may be formed by the dehydration of picropharmacolite.
