Blatonite

Chemical formula: (U<sup>6+</sup>O<sub>2</sub>)CO<sub>3</sub>·H<sub>2</sub>O

Blatonite is a very rare, secondary uranyl mineral, forming bright yellow, microscopic crystals and coatings.

## Characteristics Blatonite is a hydrated uranyl carbonate, occurring as very small, tabular or lath-like crystals, which rarely exceed 0.1 mm. It forms aggregates in the shape of rosettes, fans, or spherical aggregates, as well as thin coatings and efflorescences on the host rock. Due to the microscopic size of the crystals, its visual characteristics are difficult to observe without magnification. ## Physical Properties Crystals exhibit bright yellow fluorescence under ultraviolet light (both longwave and shortwave). Hardness and density have not been precisely measured due to the small size of the crystals, however, the density calculated based on the formula and unit cell parameters is 4.05 g/cm³. The mineral is highly radioactive. ## Colors and Varieties Blatonite has a characteristic bright yellow color. No varieties are distinguished. ## History and Name The mineral was described in 1999 by Paul Piret and Michel Deliens. Its name honors Norbert Blaton (born 1945), a Belgian crystallographer from the University of Antwerp, in recognition of his contributions to the crystallography of uranium minerals. ## Applications Blatonite has no industrial applications. It is of purely scientific and collector's interest as a very rare secondary uranium mineral.

Properties

Luster
Vitreous
Streak
Pale yellow
Density
4.05
Cleavage
Perfect on {010}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Blatonite is identified by its bright yellow color, characteristic strong fluorescence under UV light, and its occurrence as microscopic, tabular crystals forming aggregates. Crucial for identification is its geological environment – oxidation zones of uranium deposits. ## Differentiation from Similar Minerals It can be confused with other yellow secondary uranyl minerals, such as schoepite, metaschoepite, becquerelite, or rutherfordine. Differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or spectroscopy, due to visual similarity and microscopic crystal size. ## Crystal Forms Crystals are very small, usually tabular or lath-like, often flattened parallel to {010}. They intergrow into fan-shaped, rosette-like, or spherulitic aggregates.

Geological environment

## Genesis Blatonite is a secondary mineral, formed in the oxidation (weathering) zones of uraninite deposits. It crystallizes as a result of carbonate-rich waters acting on primary uranium ores. Its formation is associated with low-temperature conditions, close to the Earth's surface. ## Mineral Associations This mineral co-occurs with other secondary uranium minerals. In the type locality (Jáchymov), it was found in association with schoepite, rutherfordine, uraninite, as well as gypsum and hematite. ## Localities The most important and type locality for blatonite is Jáchymov (formerly Sankt Joachimsthal) in the Czech Republic. It has also been reported from the Shinkolobwe uranium mine in the Democratic Republic of Congo.

Rarity

Very rare

For collectors

## Quality Criteria The collector's appeal of blatonite depends on the richness of the aggregates and the quality of the substrate (matrix) on which it occurs. Most valued are specimens with clearly formed, though microscopic, crystalline aggregates of intense yellow color, contrasting with the host rock. Due to their size, specimens are primarily intended for collectors specializing in micromount minerals. ## Popular Localities The only source of specimens available on the collector's market is the historical locality of Jáchymov in the Czech Republic.

Care and storage

## Cleaning Blatonite specimens should not be wet cleaned. Due to its fragility and water solubility, the only safe method is gentle dust removal using a soft brush or a photographic air blower. ## What to Avoid Contact with water, acids, and other chemicals that can dissolve or damage the delicate crystals must be strictly avoided. As a uranium mineral, it is highly radioactive – exposure should be limited, hands should be washed after each contact, and it should not be stored in areas of permanent human presence. ## Storage Specimens should be stored in closed, airtight containers (e.g., micromount type) to protect them from dust, moisture, and mechanical damage. Containers should be clearly labeled as radioactive material.

Sources

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