Uvanite

Chemical formula: U<sup>6+</sup><sub>2</sub>V<sup>5+</sup><sub>6</sub>O<sub>21</sub>·15H<sub>2</sub>O

Uvanite is a rare uranium and vanadium mineral, forming dark brown to brownish-black, earthy coatings and aggregates.

## Characteristics Uvanite is a secondary mineral from the vanadate group, belonging to uranium minerals. It occurs as very fine-grained, earthy or powdery aggregates and coatings, rarely forming visible crystals. Its appearance is inconspicuous, and identification usually requires advanced analytical methods. ## Physical Properties Due to its form of occurrence (coatings, earthy aggregates), it is difficult to determine typical physical properties, such as hardness or luster, on a single crystal. The mineral is soft and brittle. It exhibits strong radioactivity due to the presence of uranium. ## Colors and Varieties Uvanite has a characteristic color ranging from brownish-black to almost black, sometimes with a brown or greenish tint. No color or commercial varieties are distinguished. ## History and Name The name "uvanite" refers to its chemical composition – uranium (U) and vanadium (VAN). The mineral was first described based on material from Temple Mountain in Emery County, Utah, USA. However, its status as a distinct mineral species was questioned for years and was ultimately discredited by the International Mineralogical Association (IMA) in 1987. It was recognized as a mixture of other vanadium and uranium minerals, mainly carnotite and uraninite. ## Applications Uvanite, as a discredited mineral species occurring in small quantities, has no industrial application. It holds only scientific and collector's significance as a historical mineralogical curiosity.

Properties

Mohs hardness
2-3
Luster
Dull
Streak
Brownish yellow
Density
2.61
Cleavage
Perfect on {010}
Fracture
Uneven
Transparency
Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Macroscopic identification of uvanite is practically impossible. Identification relies on its brownish-black color, earthy form of occurrence in association with other uranium and vanadium minerals, and, above all, its strong radioactivity. Final confirmation requires chemical (EDS) and X-ray (XRD) analysis. ## Distinguishing from similar minerals It can be confused with other dark, earthy secondary uranium and vanadium minerals, such as montroseite or various manganese oxides. The key distinguishing feature is the combination of chemical composition (uranium and vanadium) and strong radioactivity. ## Crystal Forms Uvanite occurs as earthy masses, powdery coatings, and very fine-grained aggregates. It does not form macroscopic crystals.

Geological environment

## Genesis Uvanite is a secondary mineral, forming in the oxidation zones of uranium-vanadium deposits, which occur mainly in sedimentary rocks such as sandstones and mudstones. It forms as a result of the weathering of primary uranium (e.g., uraninite) and vanadium minerals under arid conditions. ## Mineral Associations It most commonly co-occurs with other secondary uranium and vanadium minerals, such as carnotite, tyuyamunite, as well as with gypsum, calcite, and clay minerals. It often impregnates the host rock (sandstone). ## Localities Historically, it was described from the Colorado Plateau, especially from Temple Mountain in Emery County, Utah, USA. Occurrences of similar materials have also been reported in other uranium-vanadium deposits in Utah, Colorado, and Arizona.

Rarity

Very rare

For collectors

## Quality Criteria As a discredited mineral species, uvanite is not subject to standard quality assessment. Its value for collectors is historical and sentimental. Rich, well-defined aggregates on the host rock, originating from the classic, historical locality (Temple Mountain), may be prized. ## Popular Localities The only significant locality from a historical and collector's perspective is Temple Mountain in Utah, USA, from which the type material originated.

Care and storage

## Cleaning Mechanical or chemical cleaning is not recommended. Uvanite specimens are extremely brittle and sensitive. Dust generated during cleaning is radioactive and toxic. ## What to avoid It is absolutely essential to avoid inhaling dust and direct skin contact. The mineral is highly radioactive and chemically toxic. It should not be heated or exposed to any liquids. Wash hands after every contact. ## Storage Uvanite specimens must be stored in sealed, lead-lined or thick-glass containers, appropriately labeled as radioactive material. They should be kept away from other minerals that may be damaged by radiation, and away from areas of permanent human habitation.

Sources

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