Pyatenkoite-(Y)

Chemical formula: Na₅YTi₄+Si₆O₁₈·₆H₂O

Piatenkoite-(Y) is a very rare, colorless mineral with a vitreous luster, occurring as small, radial aggregates.

## Characteristics Piatenkoite-(Y) is a hydrated sodium, yttrium, and titanium silicate, belonging to the eudialyte group. It forms very small, colorless to white, acicular crystals, which typically arrange into radial or fibrous aggregates. Individual crystals rarely exceed 1 mm in length. Due to its small size and rarity, its macroscopic features are difficult to observe without magnification equipment. ## Physical Properties This mineral is characterized by a vitreous luster. It is transparent. Its Mohs hardness is approximately 5, and its calculated density is 2.63 g/cm³. It does not exhibit fluorescence under ultraviolet light. ## History and Name The mineral is named in honor of Professor Yuri A. Piatenko (1928–2012), a Russian crystallographer and mineralogist from the Institute of Mineralogy, Geochemistry, and Crystal Chemistry of Rare Elements (IMGRE) in Moscow, for his contributions to the crystal chemistry of titanium and zirconium. The suffix "-(Y)" indicates the dominant rare-earth element in its composition – yttrium. The mineral was approved by the IMA in 1996, and its discovery was first described in 1997. ## Uses Piatenkoite-(Y) has no commercial or industrial applications. It is solely an object of scientific and collecting interest for advanced collectors specializing in rare minerals or minerals from specific localities.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: White
Density: 2.63
Cleavage: Perfect on {10-10}
Fracture: Uneven
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of piatenkoite-(Y) under amateur conditions is practically impossible. It requires advanced analytical techniques such as X-ray diffraction (XRD) and chemical composition analysis (EDS/WDS). In a collection, it can be recognized based on its label and characteristic radial aggregates of small, colorless needles on a matrix rock from the type locality. ## Distinguishing from Similar Minerals It may be confused with other rare silicates from alkaline massifs, such as zirsinalite, lomonosovite, or other minerals from the eudialyte group. Differentiation requires specialized laboratory studies. ## Crystal Forms It forms acicular or bladed crystals, elongated along the [001] axis, which combine into radial, fibrous, or tangled aggregates.

Geological environment

## Genesis Piatenkoite-(Y) is a hydrothermal mineral, crystallizing in the late stages of the evolution of highly differentiated alkaline massifs. It occurs in pegmatites and hydrothermal veins cutting nepheline syenites. ## Mineral Associations At the type locality (Khibiny Massif), it co-occurs with microcline, nepheline, aegirine, lorenzenite, lomonosovite, sphalerite, galena, fluorapatite, eudialyte, and zirsinalite. ## Localities The only confirmed occurrence of piatenkoite-(Y) in the world is its type locality: Koashva Mountain in the Khibiny Massif on the Kola Peninsula, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a piatenkoite-(Y) specimen is determined almost exclusively by the abundance and well-defined form of radial aggregates on the rock matrix. Individual crystals are too small to assess their clarity or color. The best specimens are those where the aggregates are numerous, clearly visible, and contrast with the surrounding rock. The presence of rare associated minerals can further enhance the scientific and collector's value of the specimen. ## Popular Localities The only source of specimens is Koashva Mountain on the Kola Peninsula, Russia. All specimens available on the collector's market originate from this single location.

Care and storage

## Cleaning Due to the extreme rarity and fragility of specimens, mechanical cleaning is strongly discouraged. Dust can be removed very carefully using a photographic blower bulb. Any contact with water or chemicals is inadvisable without specialized knowledge. ## What to Avoid Avoid contact with all chemical agents, including acids and bases. Specimens are very brittle and susceptible to mechanical damage. Protect them from shocks, scratches, and ultrasonics. ## Storage Piatenkoite-(Y) specimens should be stored under stable conditions, in specialized collector's boxes (micromount type), which protect them from dust, moisture, and physical damage. Avoid exposure to direct sunlight and extreme temperatures.

Sources

IMA Mineral List (CNMNC)