Sileiden

Sileiden is a rare silicate mineral first described in 1998 for specimens recovered from hydrothermal veins in the Silesian Highlands in Central Europe. The name derives from Silesia, the historic region where the type locality lies. Sileiden forms colorless to pale yellow prismatic crystals with a vitreous luster. It crystallizes in the monoclinic system and has a Mohs hardness of about 6. Its chemical composition is dominated by aluminum and silicon oxides in a three-dimensional framework, with small amounts of magnesium, iron, and alkali cations balancing charge. It is classified as a tectosilicate, part of the broader framework silicate family.

Sileiden occurs in hydrothermal veins within felsic to intermediate rocks and is typically associated with quartz, muscovite, and topaz. Crystals are usually small, up to about 1.5 cm, and occur as elongated prismatic forms.

Geological significance and uses: The mineral is of interest mainly for crystallography and mineralogical research because of its unusual lattice parameters and cation distribution. It has no significant commercial applications, and gem-quality specimens are extremely rare. The type locality in the Silesian Highlands remains the best source, with additional finds reported but not widely documented.

Sileiden is named after the historic region of Silesia. As of now, only a limited number of specimens are known, and ongoing studies aim to clarify its detailed structure and formation conditions.