} Curite is a rare

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

with the chemical composition Pb₃ UO₂)₄O₄(OH)₃sub>2·2 H₂O. It is therefore a hydrated

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

uranyl

oxide An oxide () is a chemical compound containing at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion (anion bearing a net charge of −2) of oxygen, an O2− ion with oxygen in the oxidation st ...

, which forms red needles or orange, massive aggregates.

Etymology and history

Curite was first found at Shinkolobwe mine (formerly known as "Kasolo mine“) in Katanga Province in the

Democratic Republic of the Congo The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo (the last ambiguously also referring to the neighbouring Republic of the Congo), is a country in Central Africa. By land area, it is t ...

. Alfred Schoep (1881–1966) described the mineral for the first time in 1921 and named it after physicist and Nobel laureate

Pierre Curie Pierre Curie ( ; ; 15 May 1859 – 19 April 1906) was a French physicist, Radiochemistry, radiochemist, and a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. He shared the 1903 Nobel Prize in Physics with his wife, ...

(1859–1906).

Classification

The mineral is classified according to Strunz as part of the uranyl hydroxides, forming its own group with additional cations (K, Ca, Ba, Pb etc.) and primarily UO₂(O,OH)₅ pentagonal polyhedra with system number 4.GB.55. Dana classifies the mineral to the oxides and hydroxide, as part of the uranium- and thorium-containing oxides with oxidation state +6 containing Pb, Bi, hydroxyl groups or water.

Crystal structure

Curite crystallizes orthorhombically in space group Pnama with the lattice parameters ''a'' = 12.56 Å; ''b'' = 13.02 Å and ''c'' = 8.40 Å and two formula units per unit cell. The crystal structure consists of layers of corner- and edge-sharing uranyl polyhedra, in which the uranyl cation shows both pentagonal-bipyramidal and square-bipyramidal coordination. The lead cations connect these layers by coordinating to the oxygen atoms of uranyl group.

Radioactivity

The mineral is radioactive because of its uranium content of about 63%. Considering the composition with respect to the ideal sum formula, a specific activity of about 113,4 k Bq/g can be given. The absolute value of any given mineralogical sample may vary drastically depending on the general composition of the mineral with its matrix, the amount of material and its age.

Occurrence

Curite is a secondary uranium mineral, which forms by alteration of geologically old uraninite. Additionally, lead atoms form due to radioactive decay. Curite is found in the oxidation zone along with dewindtite, fourmarierite,

kasolite Kasolite is an uncommon lead uranyl silicate monohydrate mineral. It is an IMA approved mineral, that had been a valid species before the foundation of the association, that had been first described and published in 1921 by Schoep. It is a grand ...

rutherfordine Rutherfordine is a mineral containing almost pure uranyl carbonate ( U O2 CO3). It crystallizes in the orthorhombic system in translucent lathlike, elongated, commonly radiating in fibrous, and in pulverulent, earthy to very fine-grained dense ...

schoepite Schoepite, empirical formula (UO2)8O2(OH)12·12(H2O) is a rare alteration product of uraninite in hydrothermal uranium deposits. It may also form directly from ianthinite. The mineral presents as a transparent to translucent yellow, lemon ye ...

soddyite Soddyite is a mineral of uranium. It has yellow crystals and usually mixed with curite in oxidized uranium ores. It is named after the British radiochemist and physicist Frederick Soddy (1877–1956). Soddyite has been a valid species since 192 ...

sklodowskite Sklodowskite is a uranium mineral with the chemical formula: Mg(UO2)2(HSiO4)2·5H2O. It is a secondary mineral which contains magnesium and is a bright yellow colour, its crystal habit is acicular, but can form in other shapes. It has a Mohs h ...

torbernite Torbernite, also known as chalcolite, is a relatively common mineral with the chemical formula Cu UO2)(PO4)sub>2(H2O)12. It is a radioactive, hydrated green copper uranyl phosphate, found in granites and other uranium-bearing deposits as a s ...

and vandendriesscheite. Curite has been found, apart from its type locality Shinkolobwe mine, at a further 50 localities, e.g. in

Egypt Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

;

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, Australia;

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and

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, Germany; Auvergne,

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and Limousin, France;

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and

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, Italy;

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, Canada; Fianarantsoa, Madagascar; Agder and Telemark, Norway;

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, Russia; Namaqualand, South Africa;

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and

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, Czechia; Baranya and Heves, Hungary as well as in

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and

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

, USA.

Precautions

Because of its radioactivity, samples of this mineral should be kept in air-tight containers. Inhaling the dust or incorporation should be avoided.

Literature

* *

References

American Mineralogist Crystal Structure Database
AMCSD - Curite
Y. Li, P. C. Burns: ''Investigations of crystal-chemical variability in lead uranyl oxide hydrates. I. CURITE'', In: ''The Canadian Mineralogist'' 2000, ''Band 38'', S. 727–735.
PDF 363.2 kB
A. Schoep: ''La curite, nouveau minéral radioactif'' In: ''Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences'' 1921, ''173'', 1186–1187.
PDF (French) 91.6 kB
L. N. Warr: ''IMA–CNMNC approved mineral symbols'' In: '' Mineralogical Magazine'' 2021, ''85'' 291–320. DOI= 10.1180/mgm.2021.43
PDF 320 kB
''Curite'', In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Hrsg.): ''Handbook of Mineralogy, Mineralogical Society of America'', 2001
PDF 69 kB
Localities for curit
Mineralienatlas
and a
Mindat
Minda

Webminera
Curite

External links

{{Commons category, Curite * Mineralienatlas:Curit (Wiki)
Fotos von Curit auf den Webseiten der Association des Géologues Amateurs de Belgique (AGAB)
Lead minerals Oxide minerals Uranium(VI) minerals Orthorhombic minerals Minerals in space group 62