Barronite
Chemical formula: (☐<sub>0.5</sub>Ba<sub>0.5</sub>)(U<sup>6+</sup>O<sub>2</sub>)<sub>2</sub>Si<sub>5</sub>O<sub>12</sub>(OH)·2H<sub>2</sub>O
Barronite is a very rare, hydrated uranyl barium silicate, forming microscopic, yellow, platy crystals.
Properties
- Luster
- Vitreous
- Streak
- Yellow
- Transparency
- Translucent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Identification of barronite is only possible using advanced analytical methods, such as Raman spectroscopy or chemical analysis using an electron microprobe (EDS/WDS). In collecting conditions, identification relies on visual analysis under a microscope (characteristic yellow, platy crystals in radial aggregates), strong radioactivity, and knowledge of associated minerals from the type locality. ## Distinguishing from similar minerals Barronite is visually almost identical to many other secondary uranyl minerals, such as uranophane, boltwoodite, or haiweeite. Certain differentiation from these minerals without specialized analysis is impossible. ## Crystal forms It forms very small, thin, platy crystals with a rectangular or bladed outline. These crystals often combine into radial or rosetted aggregates.
Geological environment
## Genesis Barronite is a secondary uranium mineral, formed in the oxidation zone of uraninite deposits. It forms as a result of the weathering of primary uranium ores in the presence of silica- and barium-rich solutions. At the type locality, it formed in mine tailings due to atmospheric action on uranium ores. ## Mineral associations This mineral co-occurs with other secondary uranium minerals, such as haiweeite, uranophane-beta, boltwoodite, as well as quartz, calcite, and hematite. ## Localities The only confirmed occurrence of barronite in the world is the tailings of the inactive Gunnar uranium mine, located on Lake Athabasca in Saskatchewan, Canada.
Rarity
Extremely rare
For collectors
## Quality criteria Due to its extreme rarity and microscopic nature, every analytically confirmed barronite specimen is valuable to specialized collectors. Specimens with well-formed crystal aggregates, intense color, and covering as large an area as possible of the rock matrix are most highly prized. Contrast with dark host rock also enhances aesthetic appeal. ## Popular localities The only source of specimens is the type locality – the Gunnar mine in Canada. Material from this location is extremely difficult to acquire.
Care and storage
## Cleaning Barronite specimens should not be wet cleaned. Dust can only be removed with a soft brush or a photographic air blower. Any mechanical cleaning is highly inadvisable due to the fragility and small size of the crystals. ## What to avoid Contact with water, chemicals, acids, and detergents should be strictly avoided. The mineral is sensitive to changes in temperature and humidity. As a uranium mineral, it is strongly radioactive – direct skin contact, inhalation of dust, and storage in areas of permanent human habitation should be avoided. ## Storage Specimens should be stored in sealed, lead-lined or thick acrylic containers (so-called perky boxes), away from other radiation-sensitive minerals. The container must be clearly labeled as radioactive material. Store in a dry place, away from direct sunlight.