Changesite-(Ce)

Chemical formula: (Ca₈Ce₃+)&#₉₇₄₄;Fe₂+(PO₄)₇

An extremely rare lunar phosphate from the cerite supergroup, discovered in soil samples brought back by the Chinese Chang'e 5 probe from the Oceanus Procellarum region.

## Characteristics Changesite-(Ce) is a rare phosphate mineral belonging to the cerite supergroup. Chemically, it is a calcium, cerium, and iron phosphate. The only grain identified so far occurs as a colorless, transparent prismatic crystal measuring only about 10 micrometers (about one-tenth the diameter of a human hair). ## Physical properties Due to the microscopic size of the only known specimen, macroscopic physical properties such as hardness, streak, cleavage, or fracture were not directly measured. The mineral is known to be transparent and crystallizes in the trigonal system. ## Colors and varieties It occurs as colorless. It has no known varieties. ## History and name The mineral was discovered in 2022 by a team of scientists from the Beijing Research Institute of Uranium Geology. It was isolated from lunar soil samples returned to Earth in 2020 by the Chinese Chang'e 5 space mission. The mineral name honors the Chinese moon goddess, Chang'e, after whom the mission itself was named. It is the sixth new mineral discovered on the Moon. It was officially approved by the International Mineralogical Association (IMA). ## Uses Due to its extraterrestrial origin and microscopic quantity, the mineral is of purely scientific significance. Research on it provides information on the geological evolution of the Moon and igneous processes occurring on its surface.

Properties

Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identification is possible only through advanced analytical methods such as X-ray diffraction (XRD) and mass spectrometry. This requires specialized equipment capable of analyzing micrometer-sized particles. ## Distinction from similar minerals It must be distinguished from other phosphates occurring in lunar rocks, such as merrillite or apatite. Chemical analysis showing the presence of cerium and iron and precise determination of unit cell parameters are key. ## Crystal habits It forms microscopic prismatic crystals.

Geological environment

## Genesis It forms under magmatic conditions on the Moon. It was isolated from lunar basalt particles, indicating its crystallization from basaltic magma during late cooling stages. ## Mineral associations It co-occurs with other rock-forming minerals of lunar basalts. ## Localities The only known locality (locus typicus) is Statio Tianchuan in the Oceanus Procellarum (Ocean of Storms) region on the Moon, from where samples were collected by the Chang'e 5 probe.

Rarity

Extremely rare

For collectors

## Quality criteria The mineral does not exist on the collector market. The only known grain is state property and is stored in Chinese research institutions. ## Market prices No data. The mineral is completely unavailable commercially. ## Popular localities The only locality is Oceanus Procellarum on the Moon.

Care and storage

## Cleaning Specimens of this mineral are microscopic grains studied under laboratory conditions. They are not subject to standard mineralogical cleaning procedures. ## What to avoid Loss of research material, terrestrial contamination, and mechanical damage during microscopic preparation should be avoided. ## Storage Lunar samples are stored under strictly controlled laboratory conditions in a protective atmosphere (most commonly nitrogen) to prevent oxidation and the destructive effects of terrestrial moisture.

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External references

https://www.mindat.org/min-499622.html