Magnesiochangesite-(Ce)

Chemical formula: (Ca₈Ce₃+)Mg(PO₄)₇

Magnesiochangesite-(Ce) is an extremely rare phosphate from the cerite supergroup, discovered in 2024 in the Pakepake 005 meteorite.

## Characteristics Magnesiochangesite-(Ce) is an extremely rare phosphate mineral belonging to the cerite supergroup. It has been identified exclusively on a microscopic scale as a component of extraterrestrial matter. Chemically, it is an anhydrous calcium, cerium, and magnesium phosphate. Due to its origin and mode of occurrence, it does not form macroscopic crystals that could be visually evaluated with the naked eye. ## Physical properties Due to the fact that this mineral occurs as microscopic grains inside the meteorite, its macroscopic physical properties, such as Mohs hardness, streak, fracture, or cleavage, have not been determined by traditional methods. Research relies on structural and chemical analyses on a micro scale. ## Colors and varieties In transmitted light under a polarizing microscope, minerals of this group are usually colorless. Magnesiochangesite-(Ce) has no known varieties. ## History and name The mineral was officially approved by the IMA and described in 2024. Its name reflects its chemical composition - the presence of magnesium (magnesio) and cerium (Ce) - as well as its structural relationship to the mineral changesite-(Y). Changesite-(Y) itself was previously discovered in lunar soil samples brought back by China's Chang'e 5 mission, from which it took its name. ## Applications Magnesiochangesite-(Ce) has no practical or industrial applications. It is of purely scientific significance to researchers studying meteorite mineralogy, celestial body formation processes, and the evolution of planetary systems.

Properties

Crystal system: Trigonal

Diagnostic features

## Identification Identification of this mineral is impossible in field conditions. It requires advanced analytical methods, such as electron probe microanalysis (EPMA) to determine the chemical composition and electron backscatter diffraction (EBSD) or X-ray diffraction (XRD) to confirm the crystal structure. ## Distinguishing from similar minerals Magnesiochangesite-(Ce) must be distinguished from other phosphates occurring in meteorites, such as merrillite, whitlockite, or changesite-(Y). Key is a chemical analysis showing the dominance of cerium at the appropriate structural site and magnesium instead of iron. ## Crystal habits It occurs exclusively as microscopic grains embedded in the meteoritic matrix. It does not form macroscopically well-formed crystals.

Geological environment

## Genesis It is a mineral of extraterrestrial origin. It forms under specific crystallization conditions of meteoritic matter in space. ## Mineral associations It co-occurs with other minerals forming the Pakepake 005 meteorite. Exact associations depend on the petrology of the specific meteorite fragment. ## Localities The only confirmed locality (type locality) is the Pakepake 005 meteorite, found in Qiemo County (Bayingolin Prefecture, Xinjiang Region) in China.

Rarity

Extremely rare

For collectors

## Quality criteria This mineral does not occur in the form of classic collector specimens. Its value is based solely on the scientific uniqueness of the entire meteorite in which it was identified. ## Market prices No market data available. The mineral occurs on a microscopic scale in material of purely research significance. ## Popular localities The sole source is the Pakepake 005 meteorite from China.

Care and storage

## Cleaning Meteorite specimens containing this mineral require specialized laboratory treatment. They should not be cleaned using any home methods or altered in structure. ## What to avoid Moisture must be strictly avoided, as it leads to the oxidation and weathering of other meteorite components. Contact with any chemicals and exposure to mechanical damage are also strongly discouraged. ## Storage Meteoritic material is stored under strictly controlled laboratory conditions. A dry environment is required, typically using desiccators or vacuum containers, to prevent specimen degradation.

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External references

https://www.mindat.org/min-499971.html