Sphalerite "eyes-chain" from Spain.

The mineral sphalerite, also blende or sphalerite (obsolete: sphalerite), is the main source for the extraction of zinc. The mineral consists largely of ZnS, zinc sulfide, and contains about 67% zinc. However, the mineral may also contain large amounts of iron. Cadmium can also occur in recoverable quantities. The mineral often contains inclusions of chalcopyrite (CuFeS2). Sphalerite occurs regularly as contamination in ore. The mineral has a hardness of 3.5 to 4, and an average density of 4.05. The low level of hardness makes the mineral is not suitable for jewelry. Zincblende has a cubic crystal system with the space group F-43m. It may consist of tetrahedral or dodecahedrale crystals, but it usually does not have beautiful crystal forms (anhedrisch). Fission takes place according to the crystal surface [110]. Ed Weel Inging takes place along the axis (111). The mineral may be transparent to translucent, but also contains entirely opaque as much iron. The color is usually brown but can vary between colorless, dark brown, gray or black. The mineral may contain brown, pale yellow or white stripes. Sphalerite has a resinous luster. The name is derived from the Greek sphalerite sphaleros, which means "insidious". The mineral was in fact common galena (loodblende) since, but it contains no lead. Zincblende is formed in a wide variety of hydrothermal conditions. It often occurs together with pyrite and galena. The type of location of sphalerite is unspecified gedefinieer and the mineral is very common. It is considered the most important zinc ore.