Cubic Pyrite from Peru (7.2kg), brass base

Pyrite is a mineral composed of iron sulphide (FeS) and is often called "mad gold" because of its similarity with gold. It is relatively abundant in nature and is found in many parts of the world, including Peru. Pyrite usually crystallizes as cubes or cubic crystals, with well-defined edges and flat faces.
and this particular one ismade up of hundreds of magnificent dodecahedral crystals (with twelve faces), which have been given the name of Pyritohedra. In addition to its aesthetic qualities, pyrite also has industrial uses. It is sometimes used in the production of sulphuric acid and as a source of sulphur in certain industrial processes.