3.4" Metallic, Needle-Like Pyrolusite Cystals in Quartz - Morocco

Pyrolusite is a mineral consisting of manganese dioxide (MnO2) and is important as an ore of manganese. It has a silver, metallic luster, a black or bluish-black streak, and readily soils the fingers. It commonly is found in finely packed fibrous, acicular, and radial forms composed of very fine needles or fibers.

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.