Mitryaevaite

Chemical formula: Al₅(PO₄)₂[(P,S₆+)O₃(OH,O)]₂F₂(OH)₂·₁₄.₅H₂O

Mitryaevaite is an extremely rare, hydrated aluminum phosphate, forming microscopic, colorless, bladed crystals.

## Characteristics Mitryaevaite is a very rare mineral from the phosphate group. It occurs as extremely small, bladed or tabular crystals, rarely exceeding 0.2 mm in length. The crystals are colorless and transparent, often forming disordered aggregates or fan-shaped clusters. Due to its microscopic size, its visual features are difficult to observe without specialized equipment. ## Physical Properties Mitryaevaite crystals exhibit a vitreous luster. The mineral is very soft, with a Mohs hardness of only 1. It is a light mineral, with a density of approximately 2.11 g/cm³. It shows perfect cleavage in one direction. ## History and Name The mineral was approved by the IMA in 2011. Its name honors the Russian mineralogist and crystallographer, Natalia Mikhailovna Mitryaeva (1923–2010), in recognition of her contribution to the study of Kazakhstan's deposits. It was discovered in a phosphorite deposit in the Karatau mountain range in Kazakhstan.

Properties

Mohs hardness: 1
Luster: Vitreous
Streak: White
Density: 2.11
Cleavage: Perfect on {010}
Fracture: Uneven
Transparency: Transparent
Crystal system: Triclinic

Diagnostic features

## Identification Identification of mitryaevaite is practically only possible using advanced analytical methods, such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). Visually, at the occurrence site, it can be suspected based on its association with other rare phosphates within phosphorite deposits. ## Differentiation from similar minerals Due to its microscopic size and lack of characteristic macroscopic features, distinguishing it from co-occurring secondary minerals (e.g., other hydrated aluminum phosphates) is impossible without specialized studies. ## Crystal forms It forms very small, elongated crystals with a bladed or thin-tabular habit. These crystals often combine into irregular, tangled, or fan-shaped aggregates.

Geological environment

## Genesis Mitryaevaite is a secondary mineral that forms in the oxidation zones of phosphorite deposits. Its formation is associated with the weathering processes of primary minerals in an environment rich in aluminum and phosphorus. ## Mineral associations This mineral co-occurs with other rare phosphates, such as ankinovichite, kazphosphate, as well as with quartz, calcite, dolomite, opal, chalcedony, and clay minerals. ## Localities The only confirmed locality of mitryaevaite in the world is its type locality – the Chulaktau phosphorite deposit in the Karatau mountain range, Jambyl Region, southern Kazakhstan.

Rarity

Extremely rare

For collectors

## Quality criteria Due to its extreme rarity and microscopic size, every analytically confirmed specimen is extremely valuable to specialized collectors of rare minerals (so-called "micromounters"). The most highly prized specimens are those with the largest possible (though still microscopic), well-formed crystals, richly covering the rock matrix, and well-documented analytically. ## Popular localities The only source of specimens is the type locality in Kazakhstan, which makes them practically unavailable on the collector's market.

Care and storage

## Cleaning Specimens should only be cleaned with compressed air to remove dust. Any contact with water or other liquids is highly inadvisable due to the extreme delicacy and potential solubility of the mineral. ## What to avoid Avoid contact with water, chemicals, and ultrasound. The mineral is very soft and brittle, so it must be protected from any shocks and abrasions. It should not be heated, as it contains a lot of water in its crystal structure. ## Storage Mitryaevaite specimens should be stored exclusively in specialized, sealed "micromount" containers, protecting them from mechanical damage, dust, and humidity changes. Display is only possible under a microscope.

Sources

IMA Mineral List (CNMNC)