Tsangpoite

Chemical formula: Ca₅(PO₄)₂(SiO₄)

Tsangpoite is an extremely rare calcium phosphate-silicate, first identified in the D'Orbigny meteorite.

## Characteristics Tsangpoite is a microscopic mineral, occurring as small, colorless grains not exceeding 20 micrometers in size. It was discovered in the D'Orbigny meteorite, where it forms inclusions within other minerals, such as diopside. Due to its size, its visual characteristics cannot be assessed with the naked eye. ## Physical Properties As an accessory mineral of microscopic size, most of its physical properties, such as hardness, density, or luster, have not yet been thoroughly investigated and determined from macroscopic samples. It is transparent and colorless. ## History and Name The mineral's name comes from the Yarlung Tsangpo River in Tibet, near which another new mineral was discovered in 2015, inspiring the research team. Tsangpoite was formally described and approved by the International Mineralogical Association (IMA) in 2017 (IMA2017-037). Its discovery was made during the study of an angrite – a rare type of achondrite – from the D'Orbigny meteorite.

Properties

Streak
White
Transparency
Transparent
Crystal system
Hexagonal

Diagnostic features

## Identification Identification of tsangpoite is only possible using advanced laboratory techniques, such as electron microscopy (SEM) combined with chemical composition analysis (EDS/WDS) and electron backscatter diffraction (EBSD) to determine its crystal structure. Its recognition by visual methods is not possible. ## Distinguishing from Similar Minerals Tsangpoite is structurally related to apatite and other minerals from this group. Distinguishing it requires precise analysis of the phosphorus-to-silicon ratio in its structure, which is impossible to perform outside a laboratory. ## Crystal Forms This mineral occurs as anhedral (lacking well-formed faces) grains ranging from 5 to 20 micrometers in size.

Geological environment

## Genesis Tsangpoite is a mineral of extraterrestrial origin. It formed as a result of crystallization processes within the parent body of an angritic achondrite, from which the D'Orbigny meteorite originated. Its presence suggests specific conditions of high temperature and chemical composition prevailing during the formation of planetesimals in the early Solar System. ## Mineral Associations In the D'Orbigny meteorite, tsangpoite occurs in paragenesis with minerals such as diopside, anorthite, kirschsteinite, forsterite, and other silicate and phosphate phases typical of angrite meteorites. ## Localities The only confirmed locality of tsangpoite on Earth is the D'Orbigny meteorite, found in 1979 in Buenos Aires Province, Argentina. This is its type locality.

Rarity

Extremely rare

For collectors

## Quality Criteria Tsangpoite is not a collector's mineral in the traditional sense. Its value is purely scientific. The only form in which it might enter a collection is as a fragment of the D'Orbigny meteorite, whose value is determined by its mass, provenance, and scientific significance, rather than by the presence of microscopic tsangpoite grains.

Care and storage

## Cleaning Due to its microscopic size and occurrence exclusively as inclusions within the meteorite structure, individual tsangpoite grains are not subject to cleaning. Any attempts to clean a meteorite fragment should be carried out by specialized laboratories to avoid damaging its unique structure. ## What to Avoid Meteorite specimens containing tsangpoite are extremely valuable scientifically. Any chemical interventions, temperature changes, moisture, and exposure to environments that could cause oxidation or contamination of the sample should be avoided. ## Storage Fragments of the D'Orbigny meteorite should be stored under controlled conditions, preferably in containers with a regulated atmosphere (e.g., nitrogen), to prevent mineral degradation. These are objects of museum and research significance, not typical collector specimens.

External references

Sources

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