Curite

Chemical formula: Pb²⁺₃+x[(U⁶⁺O₂)₄O₄+x(OH)₃-x]₂·₂H₂O

Curite is a rare, highly radioactive uranium mineral characterized by its intense reddish-orange color and high density.

## Characteristics Curite is a complex, hydrated lead and uranium oxide, belonging to the group of secondary uranium minerals. It forms in the oxidation zones of uraninite deposits. Its most characteristic feature is its intense color, ranging from yellowish-orange, through reddish-orange, to reddish-brown. It typically occurs as earthy, powdery aggregates or crusts. Less commonly, it forms small, acicular or hair-like crystals gathered in radial aggregates or felted masses. ## Physical Properties Curite crystals, though rare, exhibit a luster ranging from adamantine to greasy or silky in the case of fibrous aggregates. The mineral is opaque; only on thin edges can it be translucent. Its Mohs hardness is 4-5. It is a very heavy mineral, with a density in the range of 7.35-7.58 g/cm³, which is noticeable even in small specimens. It is highly radioactive. ## Colors and Varieties Curite does not have named varieties. Its coloration is quite consistent and includes shades from yellow, through orange, red, to brown. Differences in hue depend on impurities and the degree of hydration. ## History and Name The mineral was first described in 1921 by Alfred Schoep. The name "curite" was given in honor of Pierre Curie (1859-1906) and Marie Skłodowska-Curie (1867-1934), pioneers in radioactivity research. The type locality, from which the first described specimens originated, is the Shinkolobwe mine in the Democratic Republic of Congo. ## Uses Due to its rarity and strong radioactivity, curite has no industrial applications. It is of purely scientific and collector's interest, being a sought-after secondary uranium mineral.

Properties

Mohs hardness: 4-5
Color: Deep to light red-orange, orange, scarlet, yellow
Luster: Adamantine to greasy
Streak: Orange
Density: 6.98
Cleavage: On {100}
Fracture: Uneven
Transparency: Transparent,Translucent
Crystal system: Orthorhombic

Diagnostic features

## Identification Curite is relatively easy to identify based on its intense, orange-red color, high density, and strong radioactivity, easily detectable with a Geiger counter. It often occurs in characteristic earthy or acicular aggregates on uraninite. ## Distinguishing from Similar Minerals Curite can be confused with other secondary uranium minerals of similar color, such as fourmarierite (reddish-orange, but with lower density) or becquerelite (yellow to yellowish-orange). Definitive differentiation often requires advanced methods like X-ray diffraction (XRD), but in collecting practice, the intensity of color, form of occurrence, and radiation strength are key. ## Crystal Forms Curite crystals are rare and usually microscopic in size. They have an acicular or hair-like habit, often elongated along one axis. They typically form radial aggregates, felted coatings, and most commonly occur as earthy and powdery masses.

Geological environment

## Genesis Curite is a secondary mineral, forming exclusively in the oxidation (weathering) zones of hydrothermal vein deposits rich in uraninite. It forms as a result of the alteration of uraninite by lead-bearing waters. It is one of the first weathering products of uraninite. ## Mineral Associations This mineral almost always occurs in direct proximity to uraninite, which is its parent mineral. It co-occurs with a wide range of other secondary uranium minerals, such as torbernite, kasolite, soddyite, becquerelite, schoepite, fourmarierite, as well as with galena (as a source of lead) and quartz. ## Localities The most important and historical locality for curite, from which the world's best specimens originate, is the Shinkolobwe mine in Katanga Province (Democratic Republic of Congo). Other known localities include the Wölsendorf mine in Bavaria (Germany), the Great Bear Lake region in Canada, as well as some deposits in Utah (USA) and Jáchymov (Czech Republic).

Rarity

Rare

For collectors

## Quality Criteria The most highly prized curite specimens are those with well-formed, macroscopic crystals in the form of acicular, radial aggregates. An intense, deep reddish-orange color is a key factor increasing value. Attractiveness is also enhanced by a contrasting placement on a light matrix rock or in association with other colorful uranium minerals. Due to the nature of the mineral, clarity is not a typical criterion – the form and aesthetics of the aggregate are what matter. ## Popular Localities By far the most sought-after and classic specimens come from the Shinkolobwe mine in the Democratic Republic of Congo. They are considered the global standard for this mineral. Specimens from other localities, such as Wölsendorf in Germany, are also valued but rarely match the quality of those from Congo.

Care and storage

## Cleaning Curite specimens are generally not cleaned. Due to its fragility, softness, and potential risk (radioactivity), any mechanical (brushes) or chemical cleaning should be avoided. Only very careful removal of loose dust with a photographic air blower is permissible. ## What to Avoid Contact with water and chemicals must be strictly avoided. The mineral is sensitive to changes in humidity. It should not be heated. Most importantly, avoid inhaling dust and direct skin contact due to its strong radioactivity. After any contact with a specimen, hands should be thoroughly washed. ## Storage Curite must be stored in accordance with safety regulations for radioactive materials. It should be kept in a sealed, lead or glass container, away from other minerals that could be damaged by radiation. The container should be clearly marked with a radioactivity symbol. Store in a place inaccessible to children and pets, away from areas of permanent human habitation.