2.1" Chalcopyrite, Pyrite, Galena and Quartz Association - Peru
This is a beautiful specimen that contains an association of chalcopyrite, galena, pyrite and quartz crystals. It comes from the Huanzala Mine in Peru and the entire specimen measures 2.1" long. There is also a small fluorite crystal on this specimen, though it is colorless and difficult to see.
Silicon Dioxide, also known as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.
Galena is a lead based mineral that is in fact the primary ore of lead, and has been used for its lead content for thousands of years. Galena typically displays a gray metallic luster and forms cubes or octahedral crystals. The chemical composition of galena is PbS.
Pyrite or iron pyrite is commonly referred to as Fool's Gold because it's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold. In the old mining days, Pyrite was sometimes mistaken for Gold. Pyrite is the most common of the sulfide minerals with the chemical formula FeS2. Pyrite crystals occur in many shapes and habits. Smaller (druzy) crystal aggregates may give off a beautiful glistening effects, and larger crystals may be perfectly formed, including fascinating cubes, penetration twins, and other interesting crystal forms.
Chalcopyrite is a brass-yellow colored mineral which is one of the most important ores of copper. When weathered chalcopyrite loses it's metallic luster, turning a gray-green color. When acids are present the tarnish can develop a red to blue to purple iridescence.