Pyrite
Because of the metallic luster and golden color, pyrite has sometimes been mistaken for gold, leading to its nickname as "fool's gold." The mineral's isometric crystals appear as cubes or pyritohedron (12 irregular, pentagonal or five-sided faces). Pyrite has the same chemistry as marcasite, but a different structure. It is a very common mineral, found in many parts of the world. The specimens on this site are from Peru.
Chemistry: Iron Disulfide ♦ Group: Sulfides ♦ Color: pale brass yellow, dull gold ♦ Luster: metallic ♦ Transparency: opaque ♦ Crystal system: isometric ♦ Moh's hardness: 6 - 6.8 ♦ Localities: include USA, Peru, Germany, Russia, Spain and South Africa.