Trogtalite
Trogtalite
Sulfide mineral
Trogtalite is a rare selenide mineral with the formula CoSe2. It crystallizes in the cubic system and is part of the pyrite group, consisting of Co2+ and Se22− ions. It has a rose-violet colour and its crystals are opaque.[2] It often occurs as grains. It was thought to be dimorphous with hastite, but this was discredited in 2009.[3] Hastite turned out to be the iron selenide mineral ferroselite.[4] It forms a solid solution series with kruťaite.