Tags: Chemical Substance, Mineral.
Pharmacosiderite is a hydrated basic ferric arsenate with chemical formula KFe4(AsO4)3(OH)4·(6-7)H2O and a molecular weight of 873.38 g/mol. It consists of the elements arsenic iron hydrogen potassium sodium and oxygen. It has a Mohs hardness of 2 to 3 about that of a finger nail. Its specific gravity is about 2.7 to 2.9 has indistinct cleavage and is usually transparent or translucent. It has a yellow or white streak and a yellow green brown or red color.
