Tschaunerite

Chemical formula: (Fe²⁺)(Fe²⁺Ti⁴⁺)O₄

Tschaunerite is an extremely rare iron and titanium oxide, identified in the Shergotty Martian meteorite.

## Characteristics Tschaunerite is an iron and titanium oxide belonging to the marokite supergroup. It was identified as microscopic, submicrometer grains in the Shergotty Martian meteorite, which fell in India in 1865. Due to the extremely small size of the crystals, its visual features are not observable with the naked eye. In microscopic studies, it appears as black, opaque grains. ## Physical Properties The mineral is opaque and black in color. Its density, calculated based on unit cell parameters, is 6.41 g/cm³. Hardness and other physical properties have not been determined due to the microscopic size of the grains. ## History and Name Tschaunerite was officially approved by the International Mineralogical Association (IMA) in 2017. Its name honors Oliver Tschauner, a mineralogist and crystallographer from the University of Nevada, Las Vegas, for his contributions to the discovery of new high-pressure minerals, often using synchrotron methods. The discovery was made during a re-examination of the Shergotty meteorite's composition.

Properties

Density
6.41
Transparency
Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Identification of tschaunerite is only possible using advanced analytical techniques, such as precession electron diffraction (PED) and energy-dispersive X-ray spectroscopy (EDS) on samples prepared using focused ion beam (FIB). Visual identification is not possible. ## Distinguishing from Similar Minerals Tschaunerite coexists with other titanium and iron oxides, such as ilmenite, ulvöspinel, and titanomagnetite. Differentiation requires precise analysis of crystal structure and chemical composition at the microscale. ## Crystal Forms The mineral forms submicrometer, anhedral (irregularly shaped) grains up to 500 nanometers in size.

Geological environment

## Genesis Tschaunerite is a high-pressure mineral. It is believed to have formed through crystallization from magma under conditions present in the Martian mantle. Alternatively, it could have formed during the meteorite impact that ejected the rock from the surface of Mars into space, as a result of shock metamorphism. ## Mineral Associations This mineral occurs in the Shergotty meteorite in paragenesis with pyroxenes (pigeonite, augite), maskelynite (a glassy form of plagioclase), titanomagnetite, ilmenite, and other oxide phases. ## Localities The only confirmed locality for tschaunerite is the Shergotty Martian meteorite, which fell in the Gaya district, Bihar state, India.

Rarity

Extremely rare

For collectors

## Quality Criteria Since tschaunerite is a microscopic mineral, it does not exist on the collector's market as a separate specimen. Its value is purely scientific. The only way to possess it is to acquire a fragment of the Shergotty meteorite, which is extremely rare and costly. The value of such fragments depends on their mass and documented provenance, not on the presence of specific microminerals.

Care and storage

## Cleaning Due to its microscopic size and occurrence solely as inclusions within the meteorite, specimens are not cleaned in the traditional sense. ## What to Avoid Meteorite specimens containing tschaunerite should be protected from moisture, chemicals, and extreme temperature changes to prevent degradation of the entire sample. ## Storage Shergotty meteorite samples are stored under controlled conditions in research institutions and museums. Collector fragments require a dry environment and protection from contaminants.

External references

Sources

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