siloite

Siloite is a mineral with the chemical formula NaMn3+Si3O9. It is a rare sodium manganese silicate and is found in pegmatites and hydrothermal veins. Siloite typically occurs as small, prismatic crystals, often exhibiting a reddish-brown to purplish hue. Its crystal structure is characterized by isolated silicate tetrahedra. The mineral was first described in 1983 and named after the Silo mine in Namibia, where it was discovered. Its physical properties include a Mohs hardness of approximately 4.5 to 5 and a density around 3.2 g/cm³. Siloite is not a common mineral and its occurrences are limited to a few specific geological locations worldwide. It is typically found in association with other manganese-bearing minerals. Due to its rarity, siloite is of interest primarily to mineral collectors and geologists studying mineral formation processes in pegmatitic and hydrothermal environments. Its formation conditions are thought to involve moderate temperatures and pressures.