Belyankinite

Chemical formula: Ca₁-₂(Ti₄+,Zr₄+,Nb₅+)₅O₁₂·₉H₂O

Belyankinite is a rare, hydrated titanium, zirconium, and niobium oxide, forming small, scaly aggregates with a yellowish tint.

## Characteristics Belyankinite is a mineral belonging to the oxide group, characterized by a complex chemical composition containing titanium, zirconium, and niobium. It occurs as very fine, scaly or platy aggregates, which can form radial clusters or thin coatings. Individual "scales" are flexible. Due to its cryptocrystalline nature, its macroscopic features are difficult to observe, and the mineral most often appears as an earthy or cryptocrystalline mass. ## Physical Properties Belyankinite is a soft mineral, with a Mohs hardness of 2-3. Its luster is described as dull or waxy. It is translucent to opaque. The mineral's density varies depending on its exact chemical composition, but measured values are around 3.3 g/cm³. ## Colors and Varieties This mineral most often takes on a color ranging from light yellow, through yellowish-brown, to brown. No named varieties are known. ## History and Name Belyankinite was first described in 1964 by G.P. Gorshkov. The mineral is named in honor of Dmitry Stepanovich Belyankin (1876–1953), a Russian petrologist and mineralogist, member of the USSR Academy of Sciences. The type locality is the pegmatites of Mount Kedykverpak in the Lovozero Massif on the Kola Peninsula, Russia. ## Applications Due to its rarity and typically small size of occurrences, belyankinite has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and for scientists.

Properties

Mohs hardness: 2-3
Luster: Waxy
Streak: Light yellow
Density: 3.3
Cleavage: Perfect on {001}
Fracture: Uneven
Transparency: Translucent to Opaque
Crystal system: Orthorhombic

Diagnostic features

## Identification Identifying belyankinite based on visual characteristics is practically impossible and requires advanced analytical methods, such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). In collector conditions, identification relies on trust in a label from a reputable source, especially if the specimen comes from a type locality. ## Distinguishing from Similar Minerals Macroscopically, it can be confused with many other earthy or cryptocrystalline secondary minerals of yellow color, such as jarosite, carnotite, or various clay minerals. Differentiation without specialized equipment is not possible. ## Crystal Forms Belyankinite forms microscopic, scaly or platy crystals that combine into spherulitic, radial, or earthy aggregates. Less commonly, it is observed as thin coatings and efflorescences on other minerals.

Geological environment

## Genesis Belyankinite is a secondary mineral, formed as a result of hydrothermal processes or weathering affecting primary niobium- and zirconium-rich minerals. It is most commonly found in alteration zones within alkaline nepheline syenite pegmatites. ## Mineral Associations This mineral co-occurs with other rare minerals of alkaline pegmatites. In the type locality (Lovozero Massif), its associations include kupletskite, lorenzenite, eudialyte, murmanite, as well as natrolite and analcime as void-filling minerals. ## Localities The most important and well-known occurrences of belyankinite are in Russia, in the alkaline massifs of the Kola Peninsula - primarily in the Lovozero Massif (e.g., Kedykverpak, Alluaiv mountains) and to a lesser extent in the Khibiny Massif. Outside Russia, its occurrence has been reported in the Mont Saint-Hilaire complex in Quebec, Canada, which is known for its extreme diversity of rare minerals.

Rarity

Very rare

For collectors

## Quality Criteria The collector appeal of belyankinite is closely related to its rarity and provenance. Specimens from the type locality (Lovozero Massif) that show distinct, rich clusters of the mineral on a rock matrix are most highly valued. The intensity of the yellow color and well-formed, though microscopic, spherulitic aggregates increase the specimen's value. Association with other rare minerals from the same environment is also important. ## Popular Localities By far the most valued and sought-after specimens by collectors come from the pegmatites of the Lovozero Massif on the Kola Peninsula in Russia. Specimens from Mont Saint-Hilaire in Canada are also desirable, but those from Russia are considered classic.

Care and storage

## Cleaning Belyankinite specimens are very delicate and soft. They should only be cleaned using compressed air to remove dust. Any contact with water, and especially with brushes, can permanently damage or destroy the specimen. ## What to Avoid Avoid contact with water and all chemicals. The mineral is susceptible to mechanical damage (scratches, abrasion) due to its low hardness. It should not be heated or subjected to ultrasound. ## Storage It is recommended to store specimens in closed, padded collector boxes to protect them from dust, shocks, and accidental touching. Avoid exposure to direct sunlight, although its specific sensitivity to UV radiation is not known.

Sources

IMA Mineral List (CNMNC)