Colomeraite

Chemical formula: NaTi<sup>3+</sup>Si<sub>2</sub>O<sub>6</sub>

Colomeraite is an extremely rare sodium-titanium pyroxene, discovered in the Jumilla meteorite, occurring as microscopic, light-green grains.

## Characteristics Colomeraite is a mineral from the pyroxene group with the chemical formula NaTi³⁺Si₂O₆. It occurs as very small, irregular (anhedral) grains, usually less than 15 micrometers in size, embedded in the rock matrix of the meteorite. Due to its microscopic size, it does not form crystals visible to the naked eye. It is characterized by a light-green color. ## Physical Properties The mineral has a vitreous luster and is translucent. Its density, calculated based on chemical composition and unit cell parameters, is 3.41 g/cm³. Hardness has not been determined due to the microscopic size of the grains. ## Colors and Varieties It is known exclusively in one color – light-green. No color or commercial varieties have been distinguished. ## History and Name Colomeraite was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 2010. Its name honors the Colomera meteorite, in which a similar but unidentified mineral phase was previously observed. Importantly, the type material, based on which colomeraite was described, comes from another Spanish meteorite – Jumilla, which fell in 1904 in Murcia. ## Applications Colomeraite has no commercial or industrial applications. It is solely an object of scientific research, providing information about processes occurring in the early Solar System.

Properties

Luster
Vitreous
Streak
White
Density
3.41
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Identification of colomeraite is impossible without advanced analytical techniques. Due to the microscopic size of the grains, its recognition requires the use of an electron microprobe (EMPA) for chemical composition analysis and electron backscatter diffraction (EBSD) to determine the crystal structure. ## Distinguishing from Similar Minerals Colomeraite coexists with other pyroxenes, such as diopside and enstatite, from which it is visually indistinguishable. The only feature allowing its identification is its unique chemical composition, specifically the simultaneous high content of sodium and titanium (in the trivalent Ti³⁺ form). ## Crystal Forms This mineral occurs exclusively in the form of anhedral (irregular, shapeless) grains ranging from a few to several micrometers in size. No well-formed crystals have been observed.

Geological environment

## Genesis Colomeraite is a mineral of extraterrestrial origin. It formed as a result of high-temperature processes in the early stages of the Solar System's formation. Its occurrence is limited to calcium-aluminum-rich inclusions (CAIs) within carbonaceous chondrites. ## Mineral Associations This mineral occurs in close association with other minerals typical of CAIs in meteorites. It is most often accompanied by diopside, forsterite, enstatite, anorthite (plagioclase), spinel, and perovskite. ## Localities The only confirmed locality of colomeraite in the world is the Jumilla meteorite – a CV3 carbonaceous chondrite that fell in the province of Murcia, Spain, in 1904.

Rarity

Extremely rare

For collectors

## Quality Criteria Colomeraite as such is not an object of collector trade, as it does not form specimens visible to the naked eye. The Jumilla meteorite itself, in which this mineral was discovered, has collector and scientific value. Meteorite specimens are valued based on their size, degree of weathering, and provenance (documented history). ## Popular Localities The only known locality is material from the Jumilla meteorite (Spain). Fragments of this meteorite are found in collections of scientific institutions and museums worldwide.

Care and storage

## Cleaning Cleaning individual colomeraite grains is not possible due to their microscopic size and tight embedding in the meteorite matrix. The parent specimen (meteorite) should not be cleaned with water or any chemical agents. ## What to Avoid The primary threat to the specimen is moisture. Meteorites, especially chondrites, are susceptible to corrosion and disintegration under the influence of atmospheric moisture. Avoid contact with chemicals, sudden temperature changes, and direct sunlight. ## Storage Meteorite fragments containing colomeraite should be stored in conditions with the lowest possible humidity. It is recommended to use a sealed container with a desiccant (e.g., silica gel) or a specialized desiccator.

Sources

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