Teineite is a rare mineral that belongs to the tennantite/tetrahedrite group. It crystallizes in the tetragonal crystal system, typically forming as prismatic or tabular crystals. It often occurs as an opaque, shiny, metallic gray or black mineral. The name "teineite" is derived from the locality where it was first discovered, at the Teine mine in Japan.
Chemically, teineite is a complex sulfosalt mineral composed of antimony, copper, lead, and sulfur. Its chemical formula is typically given as (Cu,Ag)20Pb(Sb,Bi)S13. It can also contain trace amounts of other elements, such as iron, zinc, or silver. Teineite often occurs alongside other sulfide minerals like galena, sphalerite, and chalcopyrite.
Teineite is primarily found in hydrothermal ore deposits associated with base metal deposits, particularly in polymetallic veins. These veins are often associated with precious metal ores and can be found in various geological environments worldwide.
Due to its rarity and limited commercial significance, teineite is primarily valued as a collector's mineral and for scientific research. Its unique crystal structure, composition, and occurrence provide valuable insights into the formation and physical properties of sulfosalt minerals. While not widely known beyond the world of mineral enthusiasts and specialists, teineite remains an important and intriguing mineral in the realm of geological studies.
