Marcasite

Introduction: So called because of an historic connection to a province in Persia, marcasite is a polymorph, which means it can take 'many forms'. It has the same chemical composition as pyrite but crystallizes in different systems. Marcasite has a metallic brass colour and is most common in limestone, some shales and dolomites.

Distribution: Rosh Pinah, Brandberg West Mine and the Crystal Tin Mine 25km north-west of Omaruru

Composition: Sulphide

Crystal system: Orthorhombic

Lustre: Metallic

Streak: Green-black

Hardness: 6-6.5