Changesite-(Y)

Chemical formula: (Ca<sub>8</sub>Y)&#9744;Fe<sup>2+</sup>(PO<sub>4</sub>)<sub>7</sub>

Changesite-(Y) is a rare mineral from the apatite group, a transparent, colorless calcium yttrium phosphate, discovered in lunar material.

## Characteristics Changesite-(Y) is a mineral from the apatite group, identified as small, columnar crystals in lunar basalts. Its grains are transparent and colorless, with a vitreous luster. Due to its extreme rarity and microscopic size (typically less than 5 micrometers), its visual characteristics are known only from laboratory studies of samples brought from the Moon. ## Physical Properties Changesite-(Y) crystals have a vitreous luster. Hardness and density have not been precisely measured due to the size of the samples, but as a member of the apatite group, its hardness is estimated to be around 5 on the Mohs scale. ## History and Name The mineral's name, approved by the IMA in 2022 (IMA 2022-023a), comes from the name of the mythical Chinese moon goddess, Chang'e (嫦娥). This name honors the Chinese lunar mission Chang'e 5, which in 2020 brought lunar soil samples to Earth, in which this mineral was discovered. The discovery was made by a research team from the Beijing Research Institute of Uranium Geology.

Properties

Mohs hardness
5
Luster
Vitreous
Streak
White
Transparency
Transparent
Crystal system
Hexagonal

Diagnostic features

## Identification Identification of changesite-(Y) is possible only through advanced laboratory techniques, such as single-crystal X-ray diffraction (XRD) and Raman spectroscopy. Its colorless appearance and microscopic size prevent visual identification. ## Distinguishing from Similar Minerals Changesite-(Y) is chemically and structurally similar to other minerals of the apatite group, especially fluorapatite, with which it coexists. Differentiation requires precise chemical composition analysis to confirm the dominance of yttrium (Y) in a specific structural position and the presence of iron (Fe²⁺). ## Crystal Forms The mineral forms small, prismatic or columnar crystals with a hexagonal cross-section, up to 10 micrometers long and several micrometers wide.

Geological environment

## Genesis Changesite-(Y) crystallizes in the late magmatic stage in high-titanium ilmenite basalts. It forms under conditions of very low pressure and high temperature, typical of lunar geology. Its presence indicates magmatic differentiation processes in lunar maria. ## Mineral Associations This mineral occurs in association with other minerals found in lunar basalts, such as pyroxene (clinopyroxene), plagioclase, ilmenite, troilite, olivine (fayalite), and other phosphates from the apatite group (fluorapatite). ## Localities The only confirmed locality of changesite-(Y) in the world (or rather, beyond Earth) is the landing site of the Chang'e 5 mission in the Oceanus Procellarum region on the Moon.

Rarity

Extremely rare

For collectors

## Quality Criteria Changesite-(Y) is not available on the collector's market. Its value is purely scientific and historical, as one of the few minerals discovered in extraterrestrial material. Every sample, regardless of "quality," is priceless for science. ## Market Prices The mineral is not traded commercially. Lunar samples are the property of space agencies and research institutions.

Care and storage

## Cleaning Due to its microscopic size and occurrence exclusively in lunar material, specimens are not available and are not subject to standard cleaning. ## What to Avoid As a phosphate, the mineral is likely sensitive to strong acids. All invasive chemical and physical methods should be avoided. ## Storage Samples containing changesite-(Y) are stored in specialized laboratories under strictly controlled conditions, in an inert atmosphere, to prevent oxidation and contamination.

External references

Sources

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