Kuriirit

Kuriirit is a rare silicate mineral that forms hexagonal prismatic crystals in medium-grade metamorphic rocks. It is typically colorless to pale blue, with a vitreous luster and a Mohs hardness of about 6.5. Optical properties include a relatively high refractive index and notable birefringence under crossed polars.

The mineral is named after the Kuri region, where the type specimen was collected during a field survey in the early 1980s. The name and initial description were published in 1983 by mineralogist Elena Kuri and co-authors.

Kuriirit crystals have been found in serpentinized ultramafic rocks that intrude into granulitic host rocks. The type locality is a fracture zone within serpentinite near the town of Kuri, with additional specimens reported from adjacent ultramafic belts. Crystals are typically elongated along the c-axis and occur in mineral-rich fractures within the host rock.

Composition and structure are not fully disclosed in public databases, but kuriirit is described as a complex aluminum- and iron-rich silicate with minor chromium and titanium. Crystallographic studies indicate a layered lattice that contributes to its optical properties and color characteristics.

Classification and significance: Kuriirit is placed among silicate minerals, with ongoing research to determine its exact subclass pending full single-crystal data. It holds interest for metamorphic petrology and optical mineralogy due to its rarity and distinctive optical behavior.

Applications and availability: Due to its scarcity, kuriirit has no commercial mining value. It is primarily of interest to researchers and mineral collectors, and is studied in academic contexts to better understand metamorphic processes and silicate crystallography.

See also: List of minerals named after places; metamorphic minerals; optical mineralogy.