Pyrite

One large euhedral brass-yellow cubic Pyrite embedded on a substrate. Crystal size: 2.0 cm x 2.0 cm x 2.0 cm. Pyrite (FeS2) is either pale yellow or brass-yellow in colour that can often be tarnished with black or brown film. Lustre is metallic but can be iridescent and streak is greenish-black. Hardness is 6 to 6 1/2. Pyrite usually occurs as cubes or pyritohedrons with parallel striations along the crystal faces. Pyrite can also occur has octahedrons, nodules, massive forms, fine to coarse granular, fibrous, mammillary or stalactitic.