Vesitahrat

Vesitahrat is a rare silicate mineral notable for its iridescent veining and vitreous luster. Crystals are typically prismatic to tabular and measure from a few millimeters to a few centimeters in length. The mineral often displays blue to violet hues that shift with light, a result of its internal layered structure. Under polarized light, vesitahrat exhibits strong pleochroism and pronounced optical anisotropy.

Vesitahrat was first described in 1982 from the Vesita deposit in a central mountain belt. The name is derived from the locality and from an ancient term meaning shimmer, reflecting the mineral’s characteristic play of color. Since its initial description, isolated occurrences have been reported in nearby metamorphic terranes.

Chemically, vesitahrat is a complex silicate in which vanadium is a major constituent, with trace amounts of titanium and, in some samples, fluorine. The exact composition varies between occurrences. The mineral has a Mohs hardness of about 6.0–6.5 and a specific gravity around 3.2–3.4, with limited cleavage. It may fluoresce weakly under ultraviolet light depending on impurity content.

Occurrence and formation: vesitahrat forms during high-grade metamorphism and metasomatic alteration of feldspathic rocks, typically in vein fillings within schist or granulite facies rocks. It commonly coexists with garnet, sillimanite, cordierite, and other metamorphic minerals.

Uses and significance: due to its rarity and brittleness, vesitahrat has no large-scale industrial use. It is mainly of interest to mineral collectors and researchers studying metamorphic processes. Ongoing work focuses on its crystallography, trace-element chemistry, and potential as a geothermobarometer.