Buryatite

Chemical formula: Ca₃(Si,Fe₃+,Al)S₆+O₄B(OH)₄(OH,O)₆·₁₂H₂O

Buryatite is an extremely rare mineral of the ettringite group, forming colorless, acicular crystals, known from only one locality in the world.

## Characteristics Buryatite is a complex calcium borate, sulfate, and silicate, belonging to the ettringite group. It occurs as very small, acicular crystals, which typically form radial or fibrous aggregates. Individual crystals rarely exceed 1 mm in length. The mineral is colorless to white and transparent, with a vitreous luster. ## Physical Properties Buryatite is characterized by low hardness, approximately 3 on the Mohs scale, and low density, about 1.98 g/cm³. It is brittle. Due to its microcrystalline form, other physical properties, such as cleavage or fracture, are difficult to observe. ## Colors and Varieties This mineral is colorless or white. No colored or commercial varieties are known. ## History and Name Buryatite was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 2010. Its name comes from the Republic of Buryatia in Russia, where its only known occurrence is located – the Solongo boron and iron deposit. It was described by a team of mineralogists led by Igor V. Pekov. ## Uses Due to its extreme rarity and occurrence in microscopic quantities, buryatite has no practical applications. It is solely an object of scientific and collecting interest for specialized collectors of rare minerals.

Properties

Mohs hardness: 3
Luster: Vitreous
Streak: White
Density: 1.98
Cleavage: None
Fracture: Uneven
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identifying buryatite based on visual characteristics is practically impossible and requires advanced analytical methods, such as Raman spectroscopy or X-ray microanalysis (EDS/WDS). In collecting conditions, the only reliable indication is a label confirming its origin from the only known locality (Solongo) and its co-occurrence with other minerals from that deposit. ## Distinguishing from Similar Minerals Buryatite can be easily confused with other white, acicular minerals of the ettringite group, such as ettringite or thaumasite, which often co-occur with it. Visually, it is also similar to many other minerals forming fibrous aggregates, e.g., some zeolites. Certain distinction is possible only through chemical and structural analysis. ## Crystal Forms Buryatite forms acicular or hair-like crystals, up to 1 mm in length. These crystals most often occur as radial aggregates resembling stars or chaotic, felted fibrous clusters.

Geological environment

## Genesis Buryatite is a hydrothermal mineral. It forms in the contact zone of skarn deposits, in a specific type of rock called calciphyre, rich in calcium, boron, and sulfur. ## Mineral Associations This mineral occurs in association with other minerals typical of skarns and hydrothermal processes. It is most often accompanied by thaumasite, ettringite, calcite, as well as ore minerals such as magnetite, and garnets (andradite) and vesuvianite. ## Localities The only confirmed occurrence of buryatite in the world is its type locality: the Solongo iron and boron deposit, located on the Vitim Plateau in the Republic of Buryatia, in the Siberian part of Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria Due to its extreme rarity, the primary criterion for value is the mere presence of identified buryatite on the specimen. Specimens showing well-formed, radial aggregates of acicular crystals, rather than just felted masses, are more highly valued. Contrast with a colorful rock matrix (e.g., dark magnetite) and the abundance of clusters enhance the visual appeal and value of the specimen. ## Popular Localities The only source of buryatite specimens is the Solongo deposit in Russia. Material from this locality is extremely difficult to obtain and enters the collector's market in very limited quantities, mainly through specialized dealers and scientific institutions.

Care and storage

## Cleaning Buryatite specimens are extremely delicate and brittle. Mechanical cleaning, including with brushes, should be avoided. Due to its complex chemical composition and hydration, contact with water or other liquids is not recommended. Dust can be removed very carefully using a photographic air blower or a can of compressed air, used from a distance. ## What to Avoid Contact with all chemicals, acids, and detergents must be absolutely avoided. The mineral is sensitive to high temperatures, which can lead to its dehydration and destruction. It should be protected from shocks, drops, and scratching. ## Storage It is recommended to store specimens in closed, padded "perky boxes" that protect against mechanical damage, dust, and sudden changes in humidity. It should not be exposed to direct sunlight.

Sources

IMA Mineral List (CNMNC)