Shinkolobweite
Chemical formula: Pb²⁺₁.₃₃[U⁵⁺O(OH)(U⁶⁺O₂)₅O₄.₆₇(OH)₅.₃₃](H₂O)₅
Shinkolobweite is a very rare, secondary uranium mineral with a yellow to orange-yellow color, discovered in the Democratic Republic of Congo.
Properties
- Mohs hardness
- 2
- Color
- dark reddish brown
- Luster
- Vitreous
- Streak
- light bronze-yellow
- Density
- 5.874
- Cleavage
- perfect cleavage on {010}, imperfect cleavage on {100}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Key diagnostic features include the characteristic aggregate form (rosette-like, fan-shaped), intense yellow-orange color, co-occurrence with other secondary uranium minerals, and very strong radioactivity. Final identification requires advanced methods such as X-ray diffraction (XRD). ## Distinguishing from Similar Minerals Shinkolobweite can be confused with many other secondary uranium minerals of similar color, such as becquerelite, curite, schoepite, or compreignacite. Distinguishing it based on visual characteristics is practically impossible and requires laboratory analysis. The characteristic habit of thin, tabular crystals in rosette aggregates can be a clue. ## Crystal Forms The mineral forms thin, tabular crystals with a hexagonal outline, which combine into rosettes, fans, and spherical aggregates.
Geological environment
## Genesis Shinkolobweite is a secondary mineral, formed in the oxidation zone of uraninite deposits. It forms as a result of weathering and alteration of primary uranium ores in the presence of lead-rich waters. ## Mineral Associations At the type locality (Shinkolobwe mine), it co-occurs with uraninite, becquerelite, schoepite, curite, kasolite, soddyite, torbernite, and metatorbernite. ## Localities The only confirmed locality of shinkolobweite in the world is the Shinkolobwe mine in Katanga Province, Democratic Republic of Congo.
Rarity
Extremely rare
For collectors
## Quality Criteria The collector's appeal of a specimen depends on the size and development of the rosette aggregates, the intensity of the color, and the richness of its occurrence on the rock matrix. Specimens with clearly formed, undamaged crystal fans, contrasting with the matrix, are most valued. Due to its rarity, every specimen, even microscopic, is valuable. ## Popular Localities The only source of specimens is the historical locality at Shinkolobwe in the Democratic Republic of Congo. The mine has long been closed and flooded, meaning new specimens are not being acquired, and only materials from old collections circulate on the market.
Care and storage
## Cleaning Shinkolobweite specimens should generally not be wet-cleaned. Dust and fine particles should only be removed using a soft brush or a photographic air blower. Due to radioactivity, all handling should be performed with extreme caution, avoiding dust inhalation. ## What to Avoid Contact with water and chemicals must be strictly avoided. The mineral is sensitive to changes in temperature and humidity. As a secondary mineral, it may undergo dehydration or further alteration in an unstable environment. It should be protected from direct sunlight. ## Storage Specimens must be stored in specialized, sealed containers designed for radioactive minerals, preferably away from other radiation-sensitive minerals. The container should be clearly marked with a radioactivity symbol and stored in a location inaccessible to children and pets.