Uranospathite

Chemical formula: (Al,&#9744;)(U<sup>6+</sup>O<sub>2</sub>)<sub>2</sub>F(PO<sub>4</sub>)<sub>2</sub>·20(H<sub>2</sub>O,F)

Uranospathite is a rare uranium mineral characterized by its distinctive yellow color and platy crystals, valued by collectors of radioactive minerals.

## Characteristics Uranospathite is a hydrated aluminum uranyl phosphate. It forms characteristic, thin, platy or lamellar crystals, often grouped into rosette-like or fan-shaped aggregates. Individual crystals are typically square or rectangular in outline and can reach several millimeters in size. The mineral is strongly radioactive. ## Physical Properties Uranospathite crystals are very soft and brittle, with a Mohs hardness of approximately 2. They have a vitreous luster, and a pearly luster on cleavage surfaces. They are transparent to translucent. The mineral's density is low for a uranium mineral, around 2.5 g/cm³. ## Colors and Varieties Uranospathite occurs in shades from pale yellow to lemon yellow and golden yellow. Some specimens may exhibit a greenish tint. No named varieties are distinguished. ## History and Name The mineral's name, given in 1915 by Arthur Francis Hallimond, refers to its chemical composition (uranium) and its characteristic platy crystal form (Greek *spathe* - plate, broad leaf). It was discovered in the Redruth uranium mine in Cornwall, United Kingdom. ## Uses Due to its rarity and small accumulations, uranospathite has no industrial application. It is solely an object of interest for collectors specializing in uranium minerals.

Properties

Mohs hardness
2
Luster
Vitreous, Pearly
Streak
Pale yellow
Density
2.5
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Key diagnostic features of uranospathite include its lemon-yellow color, perfect cleavage in one direction, very low hardness, and characteristic thin, platy crystals. The mineral exhibits strong, green fluorescence under ultraviolet light (both shortwave and longwave). It is also strongly radioactive. ## Differentiation from Similar Minerals Uranospathite can be confused with other secondary uranium minerals from the autunite group, such as autunite, torbernite, or sabugalite. It differs from them mainly in crystal habit (thin plates in the case of uranospathite), as well as specific optical and physical properties. Precise identification often requires advanced research methods, such as X-ray diffraction (XRD). ## Crystal Forms Crystals are thin-tabular, platy, with a square or rectangular outline. They usually form fan-shaped, rosette-like, or radial aggregates, as well as thin coatings and crusts on host rocks.

Geological environment

## Genesis Uranospathite is a secondary uranium mineral, forming in the oxidation (weathering) zones of uranium deposits. It originates from the alteration of primary uranium minerals, such as uraninite, in the presence of phosphate-rich waters. It is a mineral of the supergene zone. ## Mineral Associations It often co-occurs with other secondary uranium minerals, such as metatorbernite, metazeunerite, bassetite, as well as with quartz, fluorite, and clay minerals. ## Localities The most important occurrences of uranospathite are historical localities in Cornwall (United Kingdom), especially in the St Just and Redruth areas. It is also known from Wölsendorf in Bavaria (Germany) and from several locations in Portugal (e.g., Bica mine).

Rarity

Rare

For collectors

## Quality Criteria The most prized by collectors are specimens with well-formed, sharp crystals forming aesthetic, fan-shaped or rosette-like aggregates. An intense, lemon-yellow color is a key factor increasing value. Contrast with the rock matrix and the absence of mechanical damage to the very brittle crystals are also important. ## Popular Localities Classic, historical specimens come from mines in Cornwall, United Kingdom. They are rare and sought after. Specimens from Wölsendorf, Germany, are also highly valued.

Care and storage

## Cleaning Uranospathite specimens should generally not be wet cleaned. Only gentle dust removal with a soft brush or a stream of compressed air from a safe distance is permissible. ## What to Avoid Contact with water and chemicals, which can damage the delicate crystals, must be strictly avoided. The mineral is sensitive to heat and can undergo dehydration (loss of water from the crystal lattice), leading to its destruction. As a radioactive mineral, it requires careful handling – avoid inhaling dust and wash hands after each contact. ## Storage Uranospathite should be stored in a sealed, lead or lead-lined container to minimize radiation emission. The container should be clearly marked as radioactive material. Store in a dry place, away from heat sources and direct sunlight.

Sources

Read more