Stilpnomelane

Stilpnomelane is a phyllosilicate mineral. It has the chemical formula K(Fe(2+),Mg,Fe(3+))8(Si,Al)12(O,OH)27*n(H2O).

Stilpnomelane occurs associated with banded iron formations. It is a metamorphic mineral associated with the blueschist and greenschist facies.

It was first described in 1827 for an occurrence in Moravia in the Czech Republic. The name is derived from the Greek stilpnos for shining, and melanos for black.