Xltä

Xltä is a rare silicate mineral reported from hydrothermal veins in the Xalta Basin. It was first described in 2010 by researchers from the University of Linara. The name Xltä derives from the Xalta language word for “glimmer.” The mineral forms in late-stage hydrothermal environments and is typically found in association with quartz, fluorite, and baryte.

Xltä crystallizes in the hexagonal system and commonly occurs as prismatic to tabular crystals. The color ranges from deep blue to emerald green, with a vitreous to resinous luster and a translucent to opaque appearance. The Mohs hardness is about 6.5. The estimated empirical formula is (Fe,Mg)3Si4O12(OH)2, with aluminum and trace rare-earth elements substituting for iron and magnesium in some samples. Its structure features a layered silicate framework with channels that can host trace water molecules.

Occurrence and geology: Xltä forms in high-temperature hydrothermal veins within metamorphosed host rocks. It is relatively scarce and is typically confined to pockets within 0.5–1.5 meters wide, often intergrown with quartz and fluorite.

Applications: Xltä has attracted interest for its potential optical properties, including weak photoluminescence under ultraviolet light and potential piezoelectric responses. However, no large-scale industrial use has been established, and specimens are primarily of interest to collectors and researchers.

See also: Mineralogy of silicates; Hydrothermal ore deposits.