THE DISCREDITATION OF HASTITE, THE ORTHORHOMBIC DIMORPH OF CoSe2, AND OBSERVATIONS ON TROGTALITE, CUBIC CoSe2, FROM THE TYPE LOCALITY

Abstract

“Hastite”, the orthorhombic dimorph of CoSe 2 , formerly considered as a valid mineral species occurring in the Trogtal quarries, Harz Mountains, Germany, is discredited as being identical with ferroselite, orthorhombic FeSe 2 . The discreditation has been unanimously approved by the IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) (IMA No. 07–E). We also provide observations on the composition, homogeneity, and origin of trogtalite (cubic CoSe 2 ) from its type locality.