Danalite

Danalite is an iron beryllium silicate sulfide mineral with formula: Fe₄Be₃(SiO₄)₃S.

It is a rare mineral which occurs in granites, tin bearing pegmatites, contact metamorphic skarns, gneisses and in hydrothermal deposits. It occurs in association with magnetite, garnet, fluorite, albite, cassiterite, pyrite, muscovite, arsenopyrite, quartz, and chlorite.