skoliasite
Skoliasite is a rare mineral belonging to the zeolite group. It was first discovered in 1967 in the Skolka mine, near Jáchymov, Czech Republic, from which it derives its name. Skoliasite is typically found in low-temperature hydrothermal veins, often associated with other zeolite minerals such as natrolite and mesolite. It is characterized by its white to colorless, prismatic crystals, which can be elongated or tabular in shape. The mineral has a Mohs hardness of 5 and a specific gravity of approximately 2.2. Skoliasite's chemical formula is NaCa2Si3O8·3H2O, indicating its composition of sodium, calcium, silicon, oxygen, and water. Its crystal structure is monoclinic, and it exhibits perfect cleavage in one direction. Due to its rarity and the specific conditions under which it forms, skoliasite is of interest to mineral collectors and researchers studying low-temperature hydrothermal processes.