Shinarumpite
Chemical formula: [Co²⁺(H₂O)₆][(U⁶⁺O₂)(S⁶⁺O₄)₂(H₂O)]·4H₂O
Shinarumpite is a very rare, hydrated uranyl cobalt sulfate, forming transparent, yellow, tabular crystals.
Properties
- Mohs hardness
- 2.5-0
- Luster
- Vitreous
- Streak
- White
- Density
- 2.58
- Cleavage
- {100}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identification of shinarumpite is possible almost exclusively under laboratory conditions using advanced methods such as X-ray diffraction (XRD) and chemical analysis (EDS). In collecting conditions, identification relies on visual analysis under a microscope (yellow color, tabular habit) and knowledge of associated minerals from the type locality. ## Distinguishing from Similar Minerals Shinarumpite can be confused with other yellow secondary uranium minerals such as metaautunite, uranophane, or carnotite. Differentiation requires specialized analysis, although the characteristic tabular habit of the crystals can be a diagnostic clue. ## Crystal Forms The mineral forms thin, tabular, bladed crystals, often grouped into small aggregates.
Geological environment
## Genesis Shinarumpite is a secondary mineral, forming in the oxidation zone of uranium deposits. It forms as a result of the weathering of primary minerals (uraninite) in the presence of sulfides (pyrite) and cobalt minerals. At the type locality, it occurs in sandy-clay sediments saturated with sulfate-rich waters. ## Mineral Associations This mineral co-occurs with other secondary uranyl sulfates. At the type locality, it was found in association with gypsum, metavoltine, romerite, siderotil, cobaltomenite, chalcanthite, epsomite, and halotrichite. ## Localities The only confirmed occurrence of shinarumpite in the world is its type locality: the Scenic Mine, located on Fry Mesa in the White Canyon mining district, San Juan County, Utah, USA.
Rarity
Extremely rare
For collectors
## Quality Criteria As a micromineral, the value of a specimen is primarily determined by the quality and size of the crystals visible under a microscope. The most desirable specimens are those with well-formed, sharp, transparent crystals, forming aesthetic groups on the matrix. Contrast with the matrix and the presence of rare associated minerals also increase collector's value. ## Popular Localities The only source of shinarumpite specimens is its type locality in Utah, USA. All specimens available on the collector's market originate from this single location.
Care and storage
## Cleaning Shinarumpite specimens are extremely delicate and usually microscopic in size. They should not be cleaned mechanically or chemically. Any attempts at cleaning risk irreversible destruction of the crystals. ## What to Avoid Avoid contact with water, which can dissolve the mineral. The crystals are very soft and sensitive to any shocks, touch, and changes in temperature and humidity. As a uranium mineral, it is radioactive and should be handled with appropriate precautions. ## Storage Specimens should be stored only in specialized, sealed "micromount" containers, protecting them from mechanical damage, dust, and humidity changes. They should be kept away from other minerals that could be damaged by radiation.