ketaspidurite

Ketaspidurite is a mineral species. It is a member of the amphibole group. Its chemical formula is (Na,K)2(Mn2+,Fe2+,Mg)5(Si8O22)(OH)2. Ketaspidurite is characterized by the presence of sodium and potassium in its A site, along with manganese, iron, and magnesium in its M sites. It has a monoclinic crystal system. Its prismatic crystals are often elongated and striated. The typical color of ketaspidurite ranges from dark brown to black. It is opaque to translucent. The streak of ketaspidurite is a pale brown. Its Mohs hardness is typically between 5 and 6. The specific gravity is around 3.3 to 3.4. Ketaspidurite is known to occur in some metamorphic rocks, particularly those that are rich in manganese. It is often found in association with other manganese-bearing minerals. The type locality for ketaspidurite is the Nima mine in the Ketaspid Plateau, China. It was first described in 2005. The mineral's name is derived from the Ketaspid Plateau where it was discovered.