Small Pyrite Cube in Matrix

A golden yellow to brown, widely occurring mineral sulfide, FeS2, Pyrite is used as an iron ore and to produce sulfur dioxide for sulfuric acid. It is also known as Fool's Gold because it resembles gold, even though it is harder (H. 5-6) and a paler yellow. Pyrite is often found in quartz veins, sometimes even with gold. Pyrite crystals are common; it may also occur as grains or in masses. It streaks a greenish black and when tarnished, may resemble chalcopyrite. If struck sharply against steel, pyrite gives off sparks. It is thought that early man carried pyrite to start fires that contributed to his survival. The name itself is derived from the Greek πυρίτης (puritēs), "of fire" or "in fire," from πύρ (pur), "fire.” Although Pyrite is fairly common, specimens such as this are highly collectable.

Like some type of "Borg" science fiction spacecraft, natural Pyrite cubes are so geometrically perfect and lustrous many people find it hard to believe they're actually looking at a natural formation.

These unique and bizarre cubes from Navajun Spain are unaltered by man. Their shapes and luster are totally natural.