Erythrite

Summary

Erythrite, also known as red cobalt, previously cobalt ochre is a secondary hydrated cobalt arsenate mineral with the formula Co3(AsO4)2•8H2O. Erythrite and annabergite, chemical formula Ni3(AsO4)2•8H2O, or nickel arsenate form a complete series with the general formula (Co,Ni)3(AsO4)2•8H2O.