Oblastite

Oblastite is a rare boron mineral with the chemical formula Ca(B3O5)OH. It is known for its unusual crystalline structure, which features a polyhedral borate anion. Oblastite typically occurs as small, translucent to transparent crystals, often colorless or pale yellow. It is found in association with other boron minerals, such as datolite and colemanite, and is generally found in metamorphic rocks that have undergone hydrothermal alteration.

The mineral was first discovered in the Khibiny Massif in the Kola Peninsula, Russia, and was named in honor of the oblast, a Russian administrative division. Since its initial discovery, oblastite has also been found in a few other locations worldwide, including the United States and Italy, though always in limited quantities. Its rarity makes it of interest to mineral collectors and researchers studying boron geochemistry.

The geological conditions required for oblastite formation are specific, typically involving a source of boron and calcium under conditions of moderate temperature and pressure, often influenced by hydrothermal fluids. Despite its rarity, the study of oblastite contributes to our understanding of the diverse and complex chemistry of boron-containing minerals and their formation environments.