Becquerelite
Chemical formula: Ca(U<sup>6+</sup>O<sub>2</sub>)<sub>6</sub>O<sub>4</sub>(OH)<sub>6</sub>·8H<sub>2</sub>O
Becquerelite is a bright yellow, secondary uranium mineral, forming small, tabular crystals with strong radioactivity.
Properties
- Mohs hardness
- 2.5
- Luster
- Vitreous
- Streak
- Yellow
- Density
- 4.85 - 5.2
- Cleavage
- Perfect on {001}
- Fracture
- Uneven
- Transparency
- Transparent to Translucent
- Crystal system
- Orthorhombic
Diagnostic features
## Identification Becquerelite is identified by its intense, bright yellow color, characteristic tabular crystal habit, and strong radioactivity, easily detectable with a Geiger counter. It often forms crusts and rosette-like aggregates on uraninite. ## Distinguishing from Similar Minerals It can be confused with other yellow secondary uranium minerals, such as fourmarierite (usually more orange or reddish), schoepite (often less transparent, can dehydrate to metaschoepite), or uranophane (usually forms acicular or fibrous aggregates). Precise identification often requires advanced research methods, such as X-ray diffraction (XRD). ## Crystal Forms Crystals are most often flattened, tabular, with a hexagonal outline, which is a result of their orthorhombic crystal system. They occur as single crystals, but more often form radial or fan-shaped aggregates, rosettes, and thin crusts on the host rock.
Geological environment
## Genesis Becquerelite is a secondary mineral, formed in the oxidation (weathering) zone of hydrothermal and pegmatitic uranium deposits. It forms as a result of the alteration of primary uraninite under the influence of oxygen- and calcium-rich waters. ## Mineral Associations It most commonly co-occurs with uraninite, which is its parent mineral. It is also accompanied by other secondary uranium minerals, such as schoepite, fourmarierite, curite, soddyite, kasolite, torbernite, and uranophane. ## Localities The most important and historical locality, which is the type locality, is the Shinkolobwe mine in Katanga Province (Democratic Republic of Congo). Other known localities include the Kasolo mine (also in Katanga), the Great Bear Lake region in Canada, deposits in Utah (USA), Wölsendorf in Bavaria (Germany), and Jáchymov in the Czech Republic.
Rarity
Rare
For collectors
## Quality Criteria The most prized becquerelite specimens are characterized by sharply formed, transparent crystals with an intense, golden-yellow color. Rich, rosette-like aggregates on a contrasting matrix, especially in association with other rare uranium minerals, are highly valued. Crystal size is crucial – specimens with crystals exceeding a few millimeters are exceptionally rare and sought after. ## Popular Localities Classic and most desired by collectors are specimens from the historical type locality – the Shinkolobwe mine in the Democratic Republic of Congo. They set the standard against which finds from other locations are compared.
Care and storage
## Cleaning Becquerelite specimens should generally not be wet cleaned. Only gentle dust removal with a soft brush or compressed air from a safe distance is permissible. Due to radioactivity, all activities should be performed with caution, avoiding inhalation of dust. ## What to Avoid Contact with water and chemicals, which can damage delicate crystals, must be strictly avoided. The mineral is sensitive to changes in humidity and can undergo dehydration (loss of water), leading to its destruction. It should not be heated or exposed to direct, intense sunlight. ## Storage Becquerelite is a strongly radioactive mineral and must be stored with special precautions. It should be kept in a tightly sealed, lead or thick glass container, away from other radiation-sensitive minerals (e.g., smoky quartz, some fluorites). The container should be clearly marked with a radioactivity symbol. Store in a dry place, away from people, especially children.