Oboniobite

Chemical formula: Mg₄Nb₅+₂O₉

Oboniobite is an extremely rare niobium and magnesium oxide, discovered in the Allende meteorite and named after a Nigerian geologist.

## Characteristics Oboniobite is a mineral from the oxide group, identified as microscopic, subhedral grains not exceeding 15 micrometers in size. It occurs as inclusions within spinel in calcium-aluminum-rich inclusions (CAIs) in the Allende carbonaceous chondrite. Due to the extremely small size of the crystals, its visual characteristics cannot be assessed with the naked eye. ## Physical Properties Due to the microscopic size of the grains, most physical properties, such as hardness, density, luster, or transparency, have not been determined. The calculated density is 4.88 g/cm³. ## History and Name The mineral was officially approved by the IMA in 2017 (IMA2017-040). Its name comes from the surname of the Nigerian geologist, Professor Sylvester A. Obono (born 1957), in recognition of his contributions to geological and mineralogical research in Nigeria. The discovery was made during the analysis of material from the Allende meteorite, which fell in Mexico in 1969.

Properties

Density: 4.88
Transparency: Opaque
Crystal system: Trigonal

Diagnostic features

## Identification Identification of oboniobite is possible only through advanced analytical techniques, such as scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), due to its microscopic size and occurrence as inclusions. In reflected light, it is gray and opaque. ## Distinguishing from Similar Minerals Distinguishing it from other microscopic oxides, such as perovskite or other niobium oxides, requires precise chemical analysis. ## Crystal Forms It is observed as very small, irregular or partially formed (subhedral) grains.

Geological environment

## Genesis Oboniobite formed in the conditions of the early Solar System, crystallizing from gas or melt in the solar nebula. Its presence in calcium-aluminum-rich inclusions (CAIs) in the Allende meteorite indicates formation at very high temperatures, as one of the first solid materials in the Solar System. ## Mineral Associations This mineral occurs as inclusions in spinel. It co-occurs with other minerals within CAIs, such as hibonite, perovskite, and melilite. ## Localities The only confirmed locality of oboniobite in the world is the Allende meteorite, which fell in Chihuahua State, Mexico.

Rarity

Extremely rare

For collectors

## Quality Criteria Oboniobite is not available on the collector's market as a separate mineral. Its value is purely scientific. The only way to possess it in a collection is to acquire a fragment of the Allende meteorite in which it has been identified, which would require specialized scientific verification. Therefore, the collector's value pertains to the meteorite itself, not the presence of oboniobite within it.

Care and storage

## Cleaning Due to its microscopic nature and occurrence as inclusions within another mineral, cleaning individual oboniobite specimens is not practiced. ## What to Avoid Specimens of the Allende meteorite, in which oboniobite is found, should be protected from moisture, chemical contaminants, and extreme temperatures to preserve the integrity of the entire sample. ## Storage Samples containing oboniobite, being fragments of the meteorite, are best stored under stable conditions in specialized containers that protect against external factors, e.g., in membrane boxes or in a dry environment.

Sources

IMA Mineral List (CNMNC)