This Specimen has been sold.
3.9" Hematite Encrusted Quartz with Chalcopyrite and Pyrite - China
This specimen displays an association of hematite encrusted quartz and pyrite crystals. Small amounts of chalcopyrite can be found scattered throughout the specimen as well. This mineral association was collected from China.
Silicon Dioxide, also know 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.
The mineral pyrite or iron pyrite is commonly referred to as Fool's Gold because its 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, including cubes of all sizes, penetration twin cubes, pyritohedral clusters and as small druzy crystals that can exhibit a beautiful glistening effect.
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.