Péligotite
Chemical formula: Na<sub>6</sub>(U<sup>6+</sup>O<sub>2</sub>)(S<sup>6+</sup>O<sub>4</sub>)<sub>4</sub>·4H<sub>2</sub>O
Péligotite is a very rare, water-soluble uranyl and sodium mineral, forming microscopic, yellow crystals.
Properties
- Mohs hardness
- 2
- Luster
- Vitreous
- Streak
- Light yellow
- Density
- 3.11
- Cleavage
- Perfect on {100}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Practical identification of péligotite requires advanced analytical methods such as Raman spectroscopy or X-ray diffraction (XRD) due to the microscopic size of its crystals. Preliminary identification in a collection is based on its bright yellow color, characteristic crystal habit (fine needles, blades, rosettes), and strong yellow fluorescence under UV light. A key feature is its water solubility. ## Distinguishing from Similar Minerals It can be confused with many other yellow secondary uranium minerals, such as natrozippeite, zippeite, uranophane, or johannite. Johannite crystallizes in the triclinic system and has a greenish-yellow color. Uranophane has a similar color but forms different aggregate habits and is not water-soluble. Definitive distinction from natrozippeite and other uranyl sulfates requires chemical analysis. ## Crystal Forms Crystals are very small, elongated, bladed or acicular. They usually occur as radial aggregates, rosettes, or chaotic clusters on the surface of the host rock.
Geological environment
## Genesis Péligotite is a secondary uranium mineral that forms in the oxidation zone of uranium deposits. It forms as a result of evaporation of mine waters rich in uranium, sodium, and sulfates in an arid climate. It forms as a post-mining product on the walls and wooden supports of mine workings. ## Mineral Associations At the type locality (Blue Lizard mine, Utah, USA), it co-occurs with gypsum, johannite, natrozippeite, as well as newly described minerals such as bluelizardite, redcanyonite, and shumwayite. These minerals form under similar conditions, crystallizing from aqueous solutions. ## Localities The only confirmed and described occurrence of péligotite in the world is its type locality – the Blue Lizard mine, Red Canyon, in San Juan County, Utah, USA.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of a péligotite specimen primarily depends on the richness and aesthetics of its microcrystalline aggregates. Specimens with clearly formed, radial aggregates of intense, bright yellow color, contrasting with a darker host rock, are most valued. Due to the microscopic nature of the mineral, the size of individual crystals is not a key criterion; rather, the abundance and coverage of the sample's surface are important. ## Popular Localities The only source of péligotite specimens is the Blue Lizard mine in Utah, USA. All samples available on the collector's market originate from this single location.
Care and storage
## Cleaning The mineral **must not be cleaned** with any liquids, including water, alcohol, or ultrasonics. It is water-soluble. To remove dust, compressed air can be used very carefully from a safe distance, or a soft brush. ## What to Avoid Contact with water and other chemicals must be strictly avoided. The mineral is sensitive to moisture and should therefore be stored in a dry environment. As a uranium mineral, it is radioactive and should be handled with appropriate precautions (avoid inhaling dust, wash hands after contact). ## Storage Péligotite specimens must be stored in sealed, dry containers, preferably with a desiccant (e.g., silica gel). They should be kept away from minerals that may be sensitive to radiation.