Strelkinite
Chemical formula: Na₂(U⁶⁺O₂)₂(V⁵⁺O₄)₂·6H₂O
Strelkinite is a rare, bright yellow uranyl vanadate mineral, found in the oxidation zones of uranium and vanadium deposits.
Properties
- Mohs hardness
- 2-2.5
- Color
- Golden yellow, yellow-green
- Luster
- Silky, Pearly
- Streak
- Light yellow
- Density
- 3.7
- Cleavage
- perpendicular to {001}
- Fracture
- Uneven
- Transparency
- Translucent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Key diagnostic features of strelkinite are its bright yellow color, earthy or powdery aggregates, and strong radioactivity, easily detectable with a Geiger counter. Under ultraviolet light (both longwave and shortwave), it shows no or very weak, greenish fluorescence. ## Distinguishing from Similar Minerals Strelkinite is visually almost identical to carnotite and tyuyamunite. Distinguishing it from these minerals without advanced analysis (chemical analysis, X-ray diffraction) is practically impossible. Carnotite contains potassium instead of sodium, and tyuyamunite contains calcium. All three minerals often co-occur. ## Crystal Forms It most commonly forms crusts, coatings, and earthy and powdery aggregates. Very small, thin, tabular or bladed crystals, which can form rosette-like aggregates, are rarely found.
Geological environment
## Genesis Strelkinite is a secondary mineral, forming in the oxidation (weathering) zones of uranium and vanadium deposits, mainly in sedimentary rocks such as sandstones and siltstones. It forms under alkaline or neutral conditions, in dry or semi-dry climates, as a result of groundwater acting on primary uranium minerals (e.g., uraninite) and vanadium. ## Mineral Associations It most commonly co-occurs with other uranyl vanadates, such as carnotite and tyuyamunite. It is also accompanied by other minerals of the oxidation zone, e.g., gypsum, calcite, barite, as well as iron and manganese oxides. ## Localities Typical localities for this mineral are the uranium-vanadium deposits on the Colorado Plateau in the USA (states of Utah, Arizona, Colorado, New Mexico). It also occurs in Kazakhstan (Mangystau Peninsula), Uzbekistan (Kyzylkum Desert), and Argentina (Mendoza Province).
Rarity
Rare
For collectors
## Quality Criteria Most valued by collectors are specimens with well-formed, even microscopic, crystals forming rosette-like aggregates. Rich, bright yellow crusts on a contrasting matrix (e.g., dark sandstone) are also highly prized. Due to their identical appearance, specimens with analytically confirmed identity (as strelkinite, not carnotite) achieve higher value. ## Popular Localities Classic and most sought-after localities include those on the Colorado Plateau in the USA, from which many intensely colored specimens originate. Specimens from Kazakhstan and Uzbekistan are also present on the collector's market.
Care and storage
## Cleaning The mineral should not be cleaned with water. For dust removal, a soft brush or compressed air from a safe distance can be used. Avoid skin contact and inhalation of dust – always wash hands after handling the specimen. ## What to Avoid Strelkinite is sensitive to water and moisture, which can lead to its slow decomposition. It should be protected from direct sunlight, which can cause fading, and from high temperatures. Avoid contact with chemicals and acids. ## Storage Strelkinite specimens must be stored in accordance with safety principles for radioactive minerals. It is recommended to keep them in sealed, lead-lined or glass containers, away from other radiation-sensitive minerals. They should be stored in a dry place, away from living areas, and clearly labeled with a warning.