Svigrúms

Svigrúms are a rare mineral species within the silicate family, first described from hydrothermal veins in the Svigrún pegmatites of the Nordex Range. They occur as slender, prismatic crystals that range from colorless to pale blue, with a vitreous to pearly luster. Chemically, svigrúms are dominated by aluminum and silicon in an aluminosilicate framework, with calcium and sodium as major interstitial cations and trace titanium and iron responsible for the observed coloration. The crystal structure has not been fully solved, but microprobe data indicate layered, sheet-like motifs typical of complex aluminosilicates.

Svigrúms form during late-stage hydrothermal crystallization in granitic pegmatites and related high-temperature metamorphic rocks. They are typically associated with quartz, garnet, tourmaline, and occasionally beryl, and are found in very limited localities worldwide.

Known occurrences are confined to a handful of deposits in the Nordex Range and a few other pegmatite belts in remote regions, contributing to their status as among the rarer mineral species.

The name svigrúm derives from the Svigrún River valley, where the type specimen was collected; the plural form "svigrúms" is used for multiple crystals or samples.

Due to rarity, svigrúms have limited industrial use but are of interest to collectors and mineralogists. They provide data on late-stage pegmatite crystallization and aluminosilicate mineralogy.