Sedovite
Chemical formula: U<sup>4+</sup>(Mo<sup>6+</sup>O<sub>4</sub>)<sub>2</sub>
Sedovite is a very rare uranium and molybdenum mineral, forming microscopic, platy crystals of an intensely black color and strong luster.
Properties
- Mohs hardness
- 2
- Luster
- Metallic to submetallic
- Streak
- Black
- Density
- 5.46
- Cleavage
- Perfect on {010}
- Fracture
- Uneven
- Transparency
- Opaque
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Amateur identification of sedovite is practically impossible. Identification requires advanced laboratory methods such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). Visually, at the occurrence site, its presence might be suspected based on black, shiny, microscopic clusters in association with other secondary uranium and molybdenum minerals. ## Distinguishing from Similar Minerals It can be confused with other black, microcrystalline minerals from oxidation zones, such as some manganese oxides, tenorite, or other rare uranium molybdates. Definitive distinction is possible only through structural and chemical analysis. ## Crystal Forms It forms very small, thin, platy crystals, often with a hexagonal or rhombic outline. These crystals typically occur as radial, rosette-like, or fan-shaped aggregates on the surface of the host rock.
Geological environment
## Genesis Sedovite is a secondary mineral, formed in the oxidation zones of hydrothermal uranium-molybdenum deposits. It forms as a result of weathering and alteration of primary uraninite and molybdenite ores under conditions of low temperatures and pressures, with access to oxygen and groundwater. ## Mineral Associations It most commonly co-occurs with other secondary uranium and molybdenum minerals. Its typical associated minerals include kalcurmolite, umohoite, wulfenite, iriginite, as well as gypsum, calcite, and quartz. ## Localities This is an extremely rare mineral, known from only a few localities worldwide. Besides the type locality in Uzbekistan, its occurrence has been confirmed, among others, at the Giveway-Simplot mine in Elko County (Nevada, USA) and in the Okcheon uranium deposit in South Korea.
Rarity
Extremely rare
For collectors
## Quality Criteria Given the microscopic nature of the mineral, the main criterion for collector value is the richness and visibility of aggregates on the rock matrix. Specimens where sedovite crystals, despite their small size, form distinct, aesthetic clusters with good luster are most prized. Association with other rare secondary minerals is also important. ## Popular Localities Sedovite specimens are practically unavailable on the collector's market. If they do appear, they almost exclusively come from historical finds from the type locality in Uzbekistan or, even more rarely, from the Nevada mine. They are highly sought after by specialized collectors of rare minerals and microminerals.
Care and storage
## Cleaning Due to its extreme rarity, microscopic size, and potential radioactivity, sedovite specimens should not be cleaned by collectors. Any conservation activities should be left to specialized laboratories. ## What to Avoid Avoid any contact with water, chemicals, and ultrasound. The mineral is very soft and brittle, so avoid shocks, friction, and temperature changes. As a uranium mineral, it emits ionizing radiation – limit exposure and avoid inhaling dust. ## Storage Specimens should be stored only in specialized, sealed containers (e.g., perky boxes), away from other minerals that could be damaged by radiation. Store in a dry place, away from heat sources and sunlight, and out of reach of children and pets.