Odintsovite

Chemical formula: K₂Na₄Ca₃Ti₄+₂Be₄Si₁₂O₃₈

An extremely rare silicate of potassium, sodium, calcium, titanium, and beryllium, found exclusively in one location worldwide.

## Characteristics Odintsovite is a very complex silicate, belonging to the group of extremely rare minerals. It forms small, usually imperfectly developed prismatic crystals or occurs as fine, disseminated grains. It is typically colorless or has a pale yellowish tint. Due to the microscopic size of its crystals, it is a mineral of interest mainly to specialized collectors and scientists. ## Physical Properties Odintsovite crystals exhibit a vitreous luster. The mineral is transparent to translucent. Its Mohs hardness is approximately 5, making it relatively soft compared to common silicates like quartz. The calculated density is 3.05 g/cm³. ## Colors and Varieties The mineral is usually colorless, less commonly pale yellow. No colored or commercial varieties are known. ## History and Name Odintsovite was recognized as a new mineral species by the International Mineralogical Association (IMA) in 1996. Its name honors Mikhail Mikhailovich Odintsov (1911-1980), a Russian geologist and director of the Institute of the Earth's Crust in Irkutsk, who made significant contributions to the study of Siberian geology. The type locality and only known occurrence is the Murun Massif in Russia. ## Uses Due to its extreme rarity and microscopic size, odintsovite has no commercial or industrial applications. It is of purely scientific and collecting interest.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: White
Density: 3.05
Cleavage: Good on {010} and {001}
Fracture: Uneven
Transparency: Transparent to Translucent
Crystal system: Orthorhombic

Diagnostic features

## Identification Identifying odintsovite based on visual characteristics is practically impossible and requires advanced analytical methods such as X-ray diffraction (XRD) or chemical microanalysis (EDS). A key clue is its occurrence in the specific geological environment of the Murun Massif, in association with charoite and other rare minerals. ## Distinguishing from Similar Minerals Based on appearance, it can be confused with many other colorless or pale yellow silicates found in the same locality, such as quartz, microcline, pectolite, or other rare minerals. Certain differentiation without specialized equipment is not possible. ## Crystal Forms Odintsovite forms small, prismatic crystals, often grouped into granular aggregates or disseminated in the host rock. Well-formed, isolated crystals are exceptionally rare.

Geological environment

## Genesis Odintsovite is a metasomatic mineral. It forms in unique, potassium-rich rocks called charoitites (or murunites), which were formed as a result of complex geological processes within the Murun Massif. ## Mineral Associations This mineral occurs in association with many other rare and unique minerals. The most important associated minerals are charoite, tinaksite, aegirine, microcline, quartz, pectolite, arfvedsonite, and rare titanosilicates. ## Localities The only confirmed occurrence of odintsovite in the world is its type locality – the Murun Massif, on the border of the Irkutsk Oblast and the Sakha Republic (Yakutia) in Siberia, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of odintsovite specimens is primarily assessed based on the presence of as well-formed and sharp crystals as possible, even if they are microscopic in size. Specimens where odintsovite is clearly visible and contrasts with the rock matrix are highly valued. Associations with purple charoite or other rare minerals from this locality are of particular value. ## Popular Localities All collector specimens come from a single location – the Murun Massif in Russia. This is the only source of this mineral in the world.

Care and storage

## Cleaning Odintsovite specimens, usually in the form of micromounts, should be cleaned with the utmost care. For dust removal, it is best to use compressed air (from a safe distance) or a very soft brush. Wet cleaning is not recommended, and if necessary, only distilled water should be used, and the specimen should be dried immediately. ## What to Avoid Avoid contact with all chemicals, including acids and detergents. Ultrasonic cleaners are absolutely forbidden, as they can destroy delicate crystals and the host rock. The mineral should be protected from sudden temperature changes. ## Storage The safest form of storage is a sealed plastic "micromount" box, which protects the specimen from dust, moisture, and mechanical damage. Each specimen should be precisely labeled with its name and locality.

Sources

IMA Mineral List (CNMNC)