Orthominasragrite
Chemical formula: V⁴⁺O(S⁶⁺O₄)(H₂O)₅
Orthominasragrite is a very rare, blue vanadium sulfate, forming microscopic coatings and aggregates in the oxidation zones of uranium-vanadium deposits.
Properties
- Mohs hardness
- 1
- Color
- Blue
- Luster
- Vitreous
- Streak
- Pale blue
- Density
- 0
- Cleavage
- Perfect on {100}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Identification of orthominasragrite is based on its characteristic pale blue color, occurrence as fine, acicular or bladed crystals forming radial aggregates, and its geological environment. It is very soft and water-soluble. Final identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Distinguishing from Similar Minerals Orthominasragrite can be confused with other secondary blue sulfates, such as chalcanthite, minasragrite, or szomolnokite. It is distinguished from chalcanthite by the absence of copper in its composition and different crystal habit. From minasragrite, which crystallizes in the monoclinic system, it can only be distinguished by crystallographic analysis. In practice, without specialized equipment, distinguishing these minerals is impossible. ## Crystal Forms Crystals are very small, bladed or acicular. They usually form radial aggregates, rosettes, spherulitic aggregates, and thin coatings on host rocks.
Geological environment
## Genesis Orthominasragrite is a secondary mineral, forming in the oxidation zones of uranium-vanadium deposits. It forms as a result of the weathering of primary vanadium-bearing minerals, such as montroseite, in the presence of sulfides (e.g., pyrite), which provide sulfate ions. It is a product of post-magmatic processes occurring at low temperatures. ## Mineral Associations This mineral coexists with other secondary vanadium and uranium minerals. It is most commonly accompanied by: minasragrite, szomolnokite, gypsum, montroseite, doloresite, and native sulfur. ## Localities The only known and confirmed occurrence of orthominasragrite (type locality) is the Carlile uranium-vanadium mine in San Juan County, Utah, USA. This is the only locality from which all specimens of this mineral studied to date originate.
Rarity
Very rare
For collectors
## Quality Criteria The quality of orthominasragrite specimens is primarily assessed based on the richness and abundance of aggregates on the rock matrix. The most desirable specimens are those with clearly visible, well-formed radial aggregates of an intensely blue color. Due to the microscopic nature of the crystals, their individual form is less important than the overall appearance and aesthetics of the coating. Contrast with the color of the host rock also enhances the attractiveness of the specimen. ## Popular Localities The only source of orthominasragrite specimens on the collector's market is its type locality – the Carlile mine in Utah, USA. All available specimens originate from this single location.
Care and storage
## Cleaning Orthominasragrite specimens are extremely delicate and sensitive to water. They should not be wet-cleaned, as the mineral is water-soluble. The safest method is to very carefully remove dust using a soft brush or a stream of compressed air from a distance. ## What to Avoid Contact with water and all chemicals must be strictly avoided. The mineral is unstable under low humidity conditions and can dehydrate, so storage in dry air and exposure to heat sources and direct sunlight should be avoided. ## Storage It is recommended to store specimens in sealed, airtight containers (so-called "perky boxes"), which help maintain a stable humidity level. They should be protected from shocks and vibrations due to their fragility.