Deynekoite

Chemical formula: Ca₉&#₉₇₄₄;Fe₃+(PO₄)₇

Deynekoite is a very rare phosphate mineral, a calcium- and iron-rich variety of merrillite, found in meteorites.

## Characteristics Deynekoite is a calcium and iron phosphate belonging to the merrillite group. It occurs as extremely small, anhedral (irregularly shaped) grains, typically less than 50 micrometers in size. It is usually found as inclusions in other minerals within meteorites. Due to its microscopic size, its visual characteristics are not observable with the naked eye. ## Physical Properties Deynekoite crystals are too small to determine their physical properties, such as hardness or density, using standard methods. The mineral exhibits a vitreous luster and is transparent. It does not show pleochroism. ## Colors and Varieties Deynekoite is colorless. No colored varieties are known. ## History and Name The mineral is named in honor of Galina Ivanovna Deyneko (born 1947), a Russian meteorite researcher from the Institute of Microelectronics Technology and High Purity Materials of the Russian Academy of Sciences in Chernogolovka. The mineral was approved by the IMA in 2019 (IMA2019-091), and its discovery was described in 2021. The type locality is the Morasko iron meteorite, found in Poland. ## Applications Due to its extreme rarity and microscopic size, deynekoite is of purely scientific and collector's interest, being an object of interest for specialized meteorite collections.

Properties

Luster: Vitreous
Streak: White
Cleavage: None
Fracture: Conchoidal
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of deynekoite is possible only through advanced laboratory techniques, such as electron microprobe (EDS/WDS) and electron backscatter diffraction (EBSD). It occurs as microscopic, colorless grains within iron meteorites. ## Distinguishing from Similar Minerals Deynekoite is visually indistinguishable from other phosphates found in meteorites, such as merrillite, brianite, or apatite. Differences can only be determined based on precise chemical composition analysis and crystallographic data. ## Crystal Forms The mineral forms exclusively anhedral, irregular grains ranging from a few to several tens of micrometers in size, occurring as inclusions in kamacite or schreibersite.

Geological environment

## Genesis Deynekoite is a mineral of extraterrestrial origin. It forms in the final stages of crystallization in IAB group iron meteorites, under conditions of very slow cooling. Its presence is associated with differentiation processes in the parent body of the asteroid. ## Mineral Associations It co-occurs with other minerals typical of iron meteorites, mainly kamacite (iron-nickel alloy), schreibersite, cohenite, troilite, and other phosphates such as brianite and merrillite. ## Localities The only confirmed locality for deynekoite is its type locality - the Morasko iron meteorite, found in the Morasko Meteorite Nature Reserve in Poznań, Poland.

Rarity

Extremely rare

For collectors

## Quality Criteria The collector's value of deynekoite is inextricably linked to the value of the meteorite specimen in which it is found. Since the mineral is invisible to the naked eye, its presence is merely a scientific curiosity that enhances the academic value of the meteorite. The most valuable are well-documented, polished slices (sections) of the Morasko meteorite, on which the location of deynekoite grains has been identified and marked. ## Popular Localities The only source of specimens is the Morasko meteorite from Poland. Specimens of this meteorite are available on the collector's market, but those with confirmed deynekoite presence are unique and are mainly found in institutional and specialized collections.

Care and storage

## Cleaning Specimens containing deynekoite (usually in the form of polished meteorite sections) should only be cleaned with a dry, soft microfiber cloth or compressed air to remove dust. Avoid any liquids and mechanical cleaning. ## What to Avoid Absolutely avoid contact with water, chemicals, acids, and cleaning agents. Iron meteorites, in which deynekoite occurs, are very susceptible to rusting. Also avoid sudden temperature changes and high humidity. ## Storage Specimens should be stored under stable conditions, preferably in sealed containers or display cases with humidity control (e.g., using silica gel). Storage in a dry environment is crucial for preventing corrosion of the parent meteorite.

Sources

IMA Mineral List (CNMNC)