A very lustrous cluster of Pyrite, accented by dark gray, metallic Sphalerite. Sphalerite consists of zinc sulfide and iron, and the darker color is typically due to a high iron content. Sphalerite is also known as "zinc blende", "black-jack" and "ruby jack", and is sometimes found with galena, calcite, dolomite, and fluorite.
Measurements: ~3-1/4" long x 2-1/2" wide x 1-1/4" thick
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.”