Okieite
Chemical formula: [Mg₃(H₂O)₁₈][V⁵⁺₁₀O₂₈]·10H₂O
Okieite is a very rare, hydrated magnesium decavanadate, forming characteristic yellow, acicular crystals.
Properties
- Mohs hardness
- 1.5
- Color
- Bright red to red orange to yellow orange
- Luster
- Silky
- Streak
- Light orange yellow
- Density
- 2.20
- Cleavage
- Perfect on {010}
- Fracture
- Conchoidal
- Transparency
- Transparent
- Crystal system
- Triclinic
Diagnostic features
## Identification Characteristic features of okieite include its intense yellow color, silky luster, and its occurrence as very fine, acicular or fibrous crystals forming radial aggregates. It is very soft and brittle. ## Distinguishing from Similar Minerals Okieite can be confused with other secondary vanadium minerals of similar color and form, such as carnotite, tyuyamunite, or pascoite. Final differentiation requires advanced analytical methods, such as Raman spectroscopy or chemical analysis (EDS/WDS), due to its unique chemical composition (it is a magnesium decavanadate). ## Crystal Forms Okieite forms very thin, acicular crystals up to 1 mm long, which combine into radial, stellate aggregates or form crusts and coatings on host rocks.
Geological environment
## Genesis Okieite is a secondary mineral, forming in the oxidation zone of uranium-vanadium deposits. It crystallizes as a result of the evaporation of mine waters in an arid climate, on the walls of mine workings. Its formation is a post-mining process, occurring under conditions of low temperature and pressure. ## Mineral Associations This mineral coexists with other secondary vanadates and sulfates. In its type locality, it was found in association with gypsum, pascoite, sherwoodite, and montmorillonite. ## Localities The only confirmed occurrence of okieite in the world is its type locality – the Burro uranium mine in the Slick Rock district, San Miguel County, Colorado, USA.
Rarity
Extremely rare
For collectors
## Quality Criteria The most valuable okieite specimens are those that show rich, dense coverage of intensely yellow, radial aggregates on a contrasting host rock. The size and completeness of these aggregates are important, as is the absence of mechanical damage, which is difficult to achieve due to the extreme fragility of the mineral. Specimens with well-defined, "stellate" groupings are particularly prized. ## Popular Localities The only source of okieite specimens is the Burro mine in Colorado, USA. Every specimen from this locality is by definition rare and sought after by collectors specializing in rare minerals, microminerals, or vanadate group minerals.
Care and storage
## Cleaning Okieite is extremely delicate and water-soluble. It must absolutely not be cleaned with water or any liquids. The safest method is to very carefully remove dust with a soft brush or a photographic air blower from a safe distance. ## What to Avoid Avoid contact with water, water vapor, and any chemicals that could dissolve or damage it. The mineral is sensitive to changes in humidity and temperature. It should not be heated or exposed to direct sunlight. Any vibrations and impacts can destroy the fragile crystals. ## Storage Specimens should be stored in stable conditions, preferably in a tightly sealed container or display case with humidity control (e.g., using silica gel). They should be protected from dust, vibrations, and direct contact with other minerals.