Chukochenite

Chemical formula: (Li<sub>0.5</sub>Al<sub>0.5</sub>)Al<sub>2</sub>O<sub>4</sub>

Chukochenite is a newly discovered mineral from the spinel group, a natural analogue of lithium aluminum oxide, found as microscopic grains in a meteorite.

## Characteristics Chukochenite is a mineral from the spinel group, approved by the IMA in 2022. It occurs as very small, anhedral (not exhibiting its own crystallographic form) grains not exceeding 15 micrometers in size. It is isostructural with spinel. It was observed as inclusions in kelyphite, an alteration product of pyrope, in a chondritic meteorite. ## Physical Properties Due to the microscopic size of the grains, most physical properties have not been experimentally determined. Hardness has been estimated based on analogy with other spinels to be approximately 7.5-8 on the Mohs scale. The density calculated from the formula and unit cell parameters is 3.635 g/cm³. The mineral exhibits a gray color in reflected light and is opaque. ## History and Name The mineral is named in honor of Chuk Chen (born 1953), known as Frank Chen, a mineral collector and philanthropist from Shanghai, China, who significantly contributed to the preservation of mineralogical specimens. The mineral was discovered in the NWA 14670 meteorite, found in Algeria in 2021.

Properties

Mohs hardness
7.5-8
Luster
Metallic
Density
3.635
Cleavage
None
Transparency
Opaque
Crystal system
Cubic

Diagnostic features

## Identification Identification of chukochenite is only possible using advanced laboratory techniques, such as Raman spectroscopy, electron microprobe analysis (EMPA), and single-crystal X-ray diffraction (SCXRD). It is impossible to distinguish under collector or field conditions. ## Distinguishing from Similar Minerals Chukochenite is visually indistinguishable from other gray, microscopic minerals of the spinel group, such as spinel (MgAl₂O₄) or hercynite (FeAl₂O₄), with which it may co-exist. Differentiation requires chemical composition analysis. ## Crystal Forms To date, it has only been observed in the form of anhedral, rounded grains of microscopic size.

Geological environment

## Genesis Chukochenite formed under high pressure and temperature conditions, likely as a result of shock processes (shock metamorphism) occurring within the parent body of the chondrite in space. It occurs in kelyphitic zones, which formed at the boundary of pyrope and olivine grains. ## Mineral Associations This mineral co-occurs with pyrope, enstatite, diopside, olivine, spinel, chromite, clinoenstatite, jadeite, and plagioclase (albite). ## Localities The only confirmed locality of chukochenite in the world is its type locality – the ordinary chondrite NWA 14670, found in 2021 in Algeria.

Rarity

Extremely rare

For collectors

## Quality Criteria As a mineral available exclusively as microscopic inclusions in one specific meteorite, it is not subject to standard quality assessment criteria used for macroscopic specimens. Its collector and scientific value lies in the very fact of the presence of an analytically confirmed mineral within the rock matrix. These specimens are of interest to scientific institutions and specialized meteorite collectors.

Care and storage

## Cleaning Due to the extremely small size of the grains and its occurrence exclusively as inclusions within the host rock (meteorite), individual crystals are not isolated or cleaned. The host specimen should be treated like a typical stony meteorite. ## What to Avoid Avoid using any chemicals, ultrasonics, or extreme temperature changes on the meteorite fragment containing chukochenite, so as not to damage the delicate structure and mineral associations. ## Storage Meteorite specimens containing this mineral should be stored under stable conditions, in a dry environment, away from direct sunlight and dust, preferably in a specialized box or display case.

Sources

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