Fluorkyuygenite

Chemical formula: Ca₁₂Al₁₄O₃₂[(H₂O)₄F₂]

Fluorkyuygenite is an extremely rare oxide mineral, a hydrated calcium and aluminum fluoride, discovered in a meteorite.

## Characteristics Fluorkyuygenite is a mineral belonging to the mayenite supergroup. It occurs as microscopic, irregular (anhedral) grains, usually not exceeding several tens of micrometers in size. Due to its size, its visual features can only be observed under high magnification. It is colorless and transparent. ## Physical Properties This mineral is characterized by a vitreous luster. Its density, calculated based on its chemical composition and unit cell parameters, is approximately 2.89 g/cm³. Hardness has not been measured due to the small size of the grains. ## Colors and Varieties Fluorkyuygenite is colorless. No colored or commercial varieties are known. ## History and Name The mineral was officially recognized by the International Mineralogical Association (IMA) in 2017. Its name refers to its chemical composition – the presence of fluorine (Fluor) – and its relation to the previously found kyuygenite. Both minerals originate from the same meteorite, Kyuygen-Khatyrka, which gave its name to kyuygenite. ## Applications Fluorkyuygenite has no commercial or industrial applications. Its significance is purely scientific, as a component of rare inclusions in meteorites, providing information about processes occurring in the early Solar System.

Properties

Luster: Vitreous
Streak: White
Density: 2.89
Cleavage: None
Transparency: Transparent
Crystal system: Isometric

Diagnostic features

## Identification Identification of fluorkyuygenite is impossible without advanced analytical equipment. Recognition is based on chemical analysis using an electron microprobe (EDS/WDS) to determine the precise composition, and on X-ray diffraction (XRD) to confirm its crystal structure. Visually, it is indistinguishable from many other colorless minerals occurring in similar parageneses. ## Distinguishing from Similar Minerals Fluorkyuygenite must be distinguished from other minerals of the mayenite supergroup, such as kyuygenite, chlorkyuygenite, mayenite, and chlormayenit. The differences lie in the dominant ion at a specific structural site – for fluorkyuygenite, it is fluorine (F), while for other minerals, it is oxygen (O) or chlorine (Cl). ## Crystal Forms This mineral does not form well-developed crystals. It occurs exclusively as anhedral (irregular, lacking crystal faces) grains within other minerals.

Geological environment

## Genesis Fluorkyuygenite forms under very specific conditions, in calcium- and aluminum-rich inclusions (CAIs - Calcium-Aluminum-rich Inclusions) within carbonaceous chondrites. Its formation is linked to processes occurring in the solar nebula at high temperatures and low pressure during the formation of the Solar System. ## Mineral Associations This mineral co-occurs with other minerals typical of CAIs in meteorites. It is most commonly associated with spinel, diopside, anorthite, grossular, as well as other minerals from the mayenite supergroup. ## Localities The only confirmed locality of fluorkyuygenite in the world is the Kyuygen-Khatyrka meteorite. This is a CV3 type carbonaceous chondrite, found in the Koryak Mountains in the Russian Far East.

Rarity

Extremely rare

For collectors

## Quality Criteria For such a rare mineral, occurring only as microscopic grains, traditional collecting criteria such as size, color, or clarity are not applicable. The value of a specimen lies solely in its scientific confirmation. The most valuable are meteorite fragments (in the form of microscopic preparations) in which the presence of fluorkyuygenite has been analytically verified by a research institution. ## Popular Localities Specimens originate exclusively from a single source – the Kyuygen-Khatyrka meteorite. This mineral is not available on the commercial collector's market and is only found in the collections of scientific institutions.

Care and storage

## Cleaning Fluorkyuygenite specimens are typically specialized scientific preparations (polished sections) containing microscopic grains embedded in a rock matrix. Cleaning by a collector is neither advisable nor possible. Any conservation treatments should only be performed by specialists under laboratory conditions. ## What to Avoid As a hydrated mineral, it may be sensitive to high temperatures, which can lead to dehydration and structural changes. Contact with strong acids and bases, which can chemically destroy it, should be avoided. It should be protected from all contaminants and moisture. ## Storage Preparations containing fluorkyuygenite should be stored in a dry, stable environment, preferably in a specialized micromineral box or a sealed container, to protect them from dust and mechanical damage.

Sources

IMA Mineral List (CNMNC)