Radovanite
Chemical formula: Cu²⁺₂Fe³⁺(As⁵⁺O₄)(As³⁺O₂OH)₂·H₂O
Radovanite is a very rare copper-iron arsenate, forming aggregates of small, tabular crystals with an intense green color.
Properties
- Color
- Pistachio green
- Luster
- glassy
- Streak
- Green
- Density
- 3.9
- Cleavage
- Indistinct
- Fracture
- Conchoidal
- Transparency
- Transparent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Amateur identification of radovanite is practically impossible. It requires advanced analytical methods, such as Raman spectroscopy or chemical analysis using an electron microprobe (EDS/WDS). An initial indication may be its intense green color, specific form of small, tabular crystals in radial aggregates, and co-occurrence with other rare arsenates. ## Distinguishing from Similar Minerals Radovanite can be confused with many other green secondary copper minerals, such as annabergite, olivenite, euchroite, or cornwallite. Differentiation requires specialized analytical equipment. Key is the determination of its chemical composition – the simultaneous presence of copper, iron, and arsenic in two different oxidation states (As³⁺ and As⁵⁺). ## Crystal Forms Radovanite forms very small, thin, tabular crystals, flattened parallel to the {010} plane. These crystals aggregate into radial or rosette-like clusters.
Geological environment
## Genesis Radovanite is a secondary mineral that forms in the oxidation (weathering) zones of ore deposits containing arsenic, copper, and iron minerals. It formed as a result of low-temperature hydrothermal processes that acted on primary ores. ## Mineral Associations At the type locality (Bukov mine, Czech Republic), radovanite occurs in association with minerals such as arsenopyrite, chalcopyrite, tennantite-(Fe), erythrite, pharmacosiderite, pitticite, bukovskýite, geminite, and gypsum. ## Localities The only confirmed occurrence of radovanite in the world is its type locality: the dumps of the Bukov uranium mine, near the town of Rožná, Vysočina Region in Moravia, Czech Republic.
Rarity
Extremely rare
For collectors
## Quality Criteria As an extremely rare mineral, every analytically confirmed radovanite specimen is valuable to specialized collectors. Most highly prized are specimens on which well-formed, even microscopic, crystals are visible, forming aesthetic, rosette-like aggregates. The richness of its occurrence on the rock matrix and the contrast with it are also important. The purity and size of individual crystals are less important than the overall quality and richness of the aggregate. ## Popular Localities The only source of radovanite specimens is its type locality in the Czech Republic. Material from this location is extremely difficult to obtain and appears on the collector's market sporadically.
Care and storage
## Cleaning Radovanite specimens should be handled with utmost care. Due to its fragility and small crystal size, mechanical cleaning is highly inadvisable. If absolutely necessary, compressed air (from a safe distance) can be used to remove dust. Avoid contact with water and any chemicals. ## What to Avoid Absolutely avoid contact with water, acids, bases, and other solvents. The mineral is potentially chemically unstable. It should be protected from high temperatures, direct sunlight, and humidity. It should not be subjected to ultrasonic cleaning. ## Storage Radovanite specimens should be stored in stable conditions, preferably in a closed, airtight "micromount" box, which protects against dust, humidity, and mechanical damage. Exposure should take place under controlled, low humidity conditions.