Feiite

Chemical formula: Fe₂+₂(Fe₂+Ti₄+)O₅

Feiite is an extremely rare iron and titanium oxide, a high-pressure polymorph of pseudobrookite, discovered in the Suizhou meteorite.

## Characteristics Feiite is a mineral from the oxide group, a high-pressure polymorph of pseudobrookite with the chemical formula Fe³⁺₂TiO₅. It occurs as extremely small, lath-like or acicular crystals, ranging in length from fractions to several micrometers. When observed in reflected light, it is grayish-white and opaque. ## Physical Properties Due to the microscopic size of the crystals, many physical properties of feiite have not been experimentally determined. Hardness is unknown. The mineral is opaque and exhibits a metallic luster. Its density, calculated based on chemical composition and unit cell parameters, is 4.69 g/cm³. ## Colors and Varieties The only observed color is grayish-white in reflected light. No colored or commercial varieties are known. ## History and Name The mineral was officially recognized by the IMA in 2017 (IMA 2017-022). Its name honors Fei Yingwei, a physicist at the Carnegie Institution for Science, for his contributions to high-pressure mineralogy research. Feiite was discovered in the Suizhou meteorite (L6 chondrite), which fell in 1986 in Hubei Province, China. ## Uses Feiite has no commercial or industrial applications. Its significance is purely scientific, as an indicator of extreme pressure and temperature conditions during shock metamorphism processes in celestial bodies.

Properties

Luster: Metallic
Density: 4.69
Cleavage: None
Transparency: Opaque
Crystal system: Orthorhombic

Diagnostic features

## Identification Identification of feiite is impossible without advanced analytical techniques. Due to the microscopic size of the crystals, recognition requires the use of a scanning electron microscope (SEM) with chemical composition analysis (EDS/WDS) and electron backscatter diffraction (EBSD) to confirm the crystal structure. A key indication is its occurrence in shock-melt veins within the Suizhou meteorite. ## Distinguishing from Similar Minerals Feiite is a polymorph of pseudobrookite (Fe₂TiO₅) and can be confused with other minerals from this group, such as ferropseudobrookite or armalcolite, as well as ilmenite. Definitive differentiation is only possible based on precise chemical and structural analysis. ## Crystal Forms It forms elongated, lath-like or acicular crystals, micrometers in size, often occurring in tangled aggregates.

Geological environment

## Genesis Feiite is a mineral formed under extremely high pressure and temperature conditions, resulting from shock metamorphism. It formed within shock veins in an L6 ordinary chondrite due to impact and rapid decompression that occurred in space. ## Mineral Associations This mineral occurs in close association with other high-pressure minerals, such as ringwoodite, wadsleyite, lingunite, and majorite-pyrope series garnets. Co-occurrence with these minerals is evidence of its genesis under shock conditions. ## Localities The only known locality of feiite in the world (type locality) is the Suizhou meteorite, found in Hubei Province, China.

Rarity

Extremely rare

For collectors

## Quality Criteria Standard quality assessment criteria for collector specimens do not apply to feiite. The value of a specimen is not based on the aesthetics of microscopic crystals, but on the fact of their presence in the meteorite matrix, confirmed by scientific research. A specimen is a polished slab or fragment of the Suizhou meteorite with documented feiite content. ## Popular Localities The only source of specimens is the Suizhou meteorite. Fragments of this meteorite are extremely rare on the collector's market and are mainly found in institutional and research collections.

Care and storage

## Cleaning Feiite specimens are microscopic inclusions within the host rock (meteorite). Cleaning individual crystals is impossible. Meteorite fragments should only be dry-cleaned, removing dust with a soft brush or a stream of compressed air. Avoid contact with water and other liquids. ## What to Avoid Absolutely avoid all chemicals, ultrasonic cleaners, and sudden temperature changes. Chondritic meteorites may contain water-soluble minerals, so contact with moisture can lead to irreversible damage to the specimen. ## Storage Specimens containing feiite should be stored under stable, dry conditions, away from direct sunlight. It is recommended to use specialized mineral or meteorite storage boxes that provide protection against dust and mechanical damage.

Sources

IMA Mineral List (CNMNC)