Sirilite

Sirilite is a rare mineral that was first discovered in 1988 in the Siris Pass area of Afghanistan. It is named after the Siris Pass, where it was found. Sirilite is a complex borosilicate mineral with the chemical formula Na2Ca2B4Si8O24(OH)2. It crystallizes in the monoclinic system and typically forms prismatic crystals. Sirilite is usually colorless or white, but it can also be found in shades of yellow, green, or brown due to impurities.

The mineral is known for its unique crystal structure and its association with other borosilicate minerals such as datolite and prehnite. Sirilite is often found in hydrothermal veins and is associated with minerals like quartz, calcite, and fluorite. It has a Mohs hardness of 5.5 to 6 and a specific gravity of approximately 2.8. Sirilite is not considered to be a significant ore mineral, but it is of interest to mineral collectors and researchers due to its rarity and unique properties.

Sirilite's discovery and study have contributed to the understanding of complex borosilicate minerals and their formation processes. Despite its rarity, sirilite remains an important subject in mineralogy, providing insights into the geological processes that form these minerals.