Magnesioleydetite
Chemical formula: Mg(U<sup>6+</sup>O<sub>2</sub>)(S<sup>6+</sup>O<sub>4</sub>)<sub>2</sub>·11H<sub>2</sub>O
Magnesioleydetite is a very rare, water-soluble uranyl mineral of the leydetite group, forming microscopic, yellow, platy crystals.
Properties
- Mohs hardness
- 2
- Luster
- Vitreous
- Streak
- Light yellow
- Density
- 2.69
- Cleavage
- Perfect on {010}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Field identification of magnesioleydetite is impossible. Identification requires advanced laboratory methods, such as X-ray diffraction (XRD) and chemical analysis (EDS). In a micromineral collection, it may be suspected based on its bright yellow color, platy crystal habit, and co-occurrence with other secondary uranyl minerals at a known locality. ## Distinguishing from similar minerals It can be confused with many other secondary uranyl sulfates, such as leydetite, johannite, or natrozippeite. Definitive differentiation is possible only through chemical analysis, which will show the dominance of magnesium over other cations. ## Crystal forms It forms very small, thin, platy crystals with a pseudohexagonal habit, often gathered in rosetted or radial aggregates and coatings.
Geological environment
## Genesis Magnesioleydeite is a secondary uranium mineral that crystallizes as a result of the evaporation of mine waters in an arid climate. It forms under low temperature and pressure conditions on the walls and beds of abandoned uranium mine workings, in the oxidation zone of deposits. ## Mineral associations At the type locality, it co-occurs with gypsum, leydetite, johannite, and other rare uranyl sulfates such as meisserite and belakovskiite. ## Localities The only confirmed occurrence worldwide (type locality) is the Blue Lizard Mine, Red Canyon, San Juan County, Utah, USA.
Rarity
Extremely rare
For collectors
## Quality criteria For micromineral collectors, specimens with well-formed, sharp crystals forming aesthetic aggregates on a contrasting matrix are most desirable. Crystal size, even if measured in micrometers, and color intensity also affect the specimen's value. Purity (lack of contamination) and abundance on the matrix are crucial. ## Popular localities The only source of specimens is the type locality – the Blue Lizard Mine in Utah, USA. Material from this location is highly valued by collectors specializing in uranium minerals and microminerals.
Care and storage
## Cleaning The mineral **must not be cleaned** with any liquids, including water, due to its complete solubility. ## What to avoid Avoid contact with water and aqueous solutions, which will dissolve it immediately. It should be protected from moisture, high temperatures, and direct sunlight, which can lead to dehydration and crystal destruction. This is a strongly radioactive mineral – exposure should be limited, and it should be stored away from other radiation-sensitive minerals. ## Storage Specimens should be stored in tightly sealed, dry containers (e.g., micromount type) to protect them from atmospheric moisture. Appropriate labeling indicating radioactivity and storage in an area isolated from living spaces is essential.