Verokäsite

Verokäsite is a rare mineral species that belongs to the schorl subgroup of the tourmaline group. Its name is derived from the island of Vero in the Baltic Sea, where it was first discovered. The mineral has a chemical composition of Na(Ca0.5,Na0.5)3Fe₆(BO₃)₃Si₆O₁₈(OH,) and crystals are typically colorless, with a hexagonal crystal system.

Physical properties of verokäsite include a Mohs hardness of around 7-7.5, a density of approximately 3.2-3.3 g/cm³, and a specific gravity of 3.31 g/cm³. It has a refractive index of 1.643-1.671, and exhibits biaxial negative optical properties.

Verokäsite was first described in 1875, by Gustave-François Niepce d'Azur, a French geologist and mineralogist. It is a relatively rare mineral, typically found in hydrothermal veins and pegmatites.

In terms of occurrence, verokäsite can be found in several countries, including Madagascar, Norway, and Russia. The mineral has also been found in hydrothermal deposits of the Baltic Sea region, specifically in Estonia.

It is worth noting that verokäsite has relatively limited industrial or economic significance. However, due to its rarity and unique properties, it is of interest to collectors and researchers of the tourmaline group. In addition, the study of verokäsite provides insights into the geological history of the regions in which it is found.