Cabvinite
Chemical formula: Th<sup>4+</sup><sub>2</sub>F<sub>7</sub>(OH)·3H<sub>2</sub>O
Cabvinit is an extremely rare thorium fluoride mineral, forming microscopic, colorless crystals and occurring in only one locality worldwide.
Description
## Characteristics Cabvinit is a hydrated thorium hydroxide fluoride, belonging to the group of extremely rare minerals. It occurs as small, spherulitic or rosette-like aggregates, which can reach up to 0.2 mm in diameter. These aggregates are composed of very small, thin, platy crystals. Due to its microscopic size, it is classified as a micromineral, and its observation requires magnification. ## Physical properties Cabvinit crystals are transparent and exhibit a vitreous luster. The density of the mineral, calculated based on its composition and crystal structure, is 4.75 g/cm³. The Mohs hardness has not yet been determined. ## Colors and varieties Cabvinit is a colorless mineral. No colored varieties or trade names are known. ## History and name The mineral was approved by the International Mineralogical Association (IMA) in 2013. Its name honors Charles "Cab" V. Vinent (1923–2005), a Californian mineral collector who collected the first samples of this mineral. The type locality, the only confirmed occurrence, is Spor Mountain in Utah, USA. ## Applications Due to its extreme rarity and microscopic size, cabvinit has no industrial applications. It is solely an object of scientific research and a valuable specimen in advanced collections of rare minerals and microminerals.
Diagnostic features
## Identification Identification of cabvinit is impossible without specialized equipment. A key diagnostic feature is its strong radioactivity, which can be detected with a Geiger counter. Visually, characteristic features are spherulitic aggregates composed of fine, platy crystals. Final confirmation requires advanced analyses, such as X-ray diffraction (XRD) and chemical composition analysis (EDS), to confirm the presence of thorium and fluorine. ## Distinguishing from similar minerals It can be confused with other colorless, secondary microminerals occurring in the same locality. Certain distinction from visually similar minerals, such as bertrandite, is possible almost exclusively based on radioactivity testing and chemical analysis. ## Crystal forms It forms spherulitic and rosette-like aggregates composed of elongated, platy crystals with orthorhombic symmetry. Individual crystals are too small to be observed with the naked eye.
Geological environment
## Genesis Cabvinit is a secondary mineral, forming under low-temperature hydrothermal conditions. It forms in voids and fractures within altered (hardened) volcanic tuffs, in deposits rich in beryllium and fluorine. ## Mineral associations It most commonly co-occurs with fluorite, bertrandite, and hematite. ## Localities The only known worldwide occurrence of cabvinit is its type locality – the bertrandite and fluorite deposit at Spor Mountain (Thomas Range), Juab County, Utah, USA.
Rarity
Extremely rare
Collector aspects
## Quality criteria In the case of a micromineral like cabvinit, the value of a specimen is primarily determined by the abundance of its occurrence – the quantity and size of aggregates on the rock matrix. Samples with well-formed, distinct spherulites or rosettes that are undamaged are most highly valued. Attractiveness is enhanced by a contrasting background, for example, darker hematite or purple fluorite. ## Popular localities All specimens available on the collector's market come from one place in the world – Spor Mountain in Utah, USA. It is a mineral sought after by specialists collecting rare species and microminerals.
Care and storage
## Cleaning Cabvinit specimens are extremely delicate and small. Mechanical or chemical cleaning is not recommended. Dust can be removed very carefully using a photographic air blower or a can of compressed air, used from a safe distance. ## What to avoid **The mineral is highly radioactive** due to its high thorium content. Inhalation of dust and direct, prolonged skin contact should be strictly avoided. Hands should be thoroughly washed after any contact with the specimen. It should not be stored in places where people spend a lot of time (desks, bedrooms). It should be protected from high temperatures, chemicals, and mechanical damage. ## Storage It is recommended to store cabvinit in a specialized lead container designed for radioactive minerals, away from other specimens in the collection, to prevent damage from radiation. The container should be clearly marked with the international radioactivity symbol. Store in a dry place.