Brunovskyite

Chemical formula: NaZr₄+Si₂O₆(OH)

Brunovskite is an extremely rare zirconium mineral, discovered in 2022 in Russia, forming microscopic, colorless crystals.

## Characteristics Brunovskite is a hydroxy-silicate of sodium and zirconium, belonging to the ekanite group of minerals. It was identified as a new mineral species by the International Mineralogical Association (IMA) in 2022. It occurs as very fine, tabular or lath-like crystals, reaching sizes up to 10-15 micrometers in length and 1-2 micrometers in thickness. These crystals form irregular clusters and aggregates. Due to its microscopic size, its visual characteristics are difficult to assess with the naked eye. ## Physical Properties Brunovskite crystals are colorless and transparent, with a vitreous luster. Hardness and density have not been experimentally determined due to the small quantity and size of the material. The density calculated based on the chemical formula and unit cell parameters is 3.29 g/cm³. ## History and Name The mineral name honors Bohuslav Brunovský (1899–1948), a Czech mineralogist and chemist from Masaryk University in Brno, for his contribution to the geochemistry of trace elements. The mineral was discovered in material from the Kedykverpakhk massif in the Khibiny Mountains on the Kola Peninsula, Russia. The holotype is housed in the collections of the A.E. Fersman Mineralogical Museum in Moscow.

Properties

Luster: Vitreous
Density: 3.29
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of brunovskite is possible only through advanced laboratory techniques, such as scanning electron microscopy (SEM) combined with chemical analysis (EDS) and electron backscatter diffraction (EBSD) or X-ray diffraction (XRD). Its microscopic size and occurrence in complex aggregates make identification impossible under field conditions or using standard optical methods. ## Distinguishing from similar minerals Brunovskite is a structural analogue of ekanite and andremeyerite. Differentiation from these and other rare zirconium silicates (e.g., elpidite, wadeite) requires precise analysis of the chemical composition, particularly the ratio of sodium, zirconium, and silicon, and analysis of the crystal structure. ## Crystal forms It forms microscopic, elongated crystals with a lath-like or tabular habit, which combine into irregular, tangled aggregates.

Geological environment

## Genesis Brunovskite forms in the late stages of hydrothermal processes in ultrabasic pegmatites, crystallizing in voids and fractures. It is a product of transformations occurring under very specific geochemical conditions, characterized by high activity of sodium and zirconium in low-temperature aqueous solutions. ## Mineral associations This mineral occurs in paragenesis with other rare minerals typical of agpaitic pegmatites. At the type locality (Khibiny massif), it was found in association with cancrinite-vishnevite, vinogradovite, lorenzenite, pekovite, delhayelite, keldyshite, rasvumite, and the newly discovered kuzmenkoite-Zn. ## Localities The only confirmed locality of brunovskite in the world is its type locality: the Kedykverpakhk massif in the Khibiny Mountains, on the Kola Peninsula, Murmansk Oblast, Russia.

Rarity

Extremely rare

For collectors

## Quality criteria As a microscopic mineral, brunovskite is not evaluated according to typical collector criteria such as size, color, or transparency of individual crystals. The value of a specimen lies in its extreme rarity, its status as type material (holotype or cotype), and the richness of the mineral association on the host rock fragment. The most valuable samples are those where the presence of brunovskite has been analytically confirmed, preferably with well-documented paragenesis of rare minerals.

Care and storage

## Cleaning Due to the extremely small size of the crystals and their rarity, brunovskite specimens should not be subjected to any mechanical or chemical cleaning methods. Any attempt at cleaning risks irreversible loss or destruction of the material. ## What to avoid Avoid any manipulation, contact with chemicals, ultrasound, as well as changes in temperature and humidity. The mineral is sensitive to acids. ## Storage Brunovskite specimens, usually in the form of polished thin sections or fragments of the host rock, should be stored exclusively under specialized, stable conditions, preferably in the original box or micropaleontological container, away from dust, light, and vibrations.

Sources

IMA Mineral List (CNMNC)