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Black, brownish-black, ...
Greasy, Sub-Metallic, Dull
5 - 6
Member of:
Re-named in 1845 by Wilhelm Karl von Haidinger for its composition containing uranium. Originally recognized before the element uranium was known and called "schwarz beck-erz" by Franz Ernst Brückmann in 1727. Subsequently described with several names including "pseudogalena" and "pitch-like zinc-blende" by Johan Gottschalk Wallerius (Vallerius) in 1747. Named pechblende by Axel Cronstedt in 1758. Named "uranerz" by Martin Klaproth after he discovered the element uranium in this mineral. Many spelling variations of the above names known.
Uraninite Group. Thorianite-Uraninite Series.

Occurs in granitic and syenitic pegmatites. Colloform crusts in high temperature hydrothermal veins. In quartz-pebble conglomerates.

Typical uranium ore contains ca. 0.1 mg of Po / metric ton; Ra is more abundant, by 0.14 g of Ra / metric ton; 231Pa is present in a very tiny amount, usually as low as 0.1 ppm, but may reach 3 ppm; traces of Np (isotopes with masses from 237 to 240) and 238Pu are also detectable. Kenna & Kuroda (1964) report values as low as 2.5–3.1 × 10−10 g for technetium (99Tc) per kg of African material. Traces of Cm are possible but not yet detected.

Compare 'UM1978-10-O:U'.

Classification of Uraninite

Approved, 'Grandfathered' (first described prior to 1959)

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
L : With large (+- medium-sized) cations; fluorite-type structures

1 : AXO2·xH2O

7 : Oxides and Hydroxides
16 : Oxides of U

Physical Properties of Uraninite

Greasy, Sub-Metallic, Dull
Diaphaneity (Transparency):
Black, brownish-black, greyish, greenish; green-gray (thin fragments)
Brownish black, grayish, olive-green
Hardness (Mohs):
5 - 6
Hardness (Vickers):
VHN50=499 - 548 kg/mm2
Irregular/Uneven, Conchoidal
10.63 - 10.95 g/cm3 (Measured)    10.88 g/cm3 (Calculated)
Decreasing with oxidation to low as 6.5

Optical Data of Uraninite

Colour in reflected light:
Light grey with brownish tint
Internal Reflections:
Dark brown

Chemical Properties of Uraninite

Elements listed in formula:
CAS Registry number:

CAS Registry numbers are published by the American Chemical Society
Analytical Data:
Sector zoning possible (e.g., Roode pegmatite, Norway: {100} sectors have a bit more U, and the {111} ones more Th, Y, and REE; Alexandre et al., 2016)
Common Impurities:

Crystallography of Uraninite

Crystal System:
Class (H-M):
m3m (4/m 3 2/m) - Hexoctahedral
Space Group:
Cell Parameters:
a = 5.4682 Å
Unit Cell Volume:
V 163.51 ų (Calculated from Unit Cell)
Octahedral, cubo-octahedral, and cubic crystals; dodecahedrons less common. Massive, botryoidal, reniform, banded, columnar, curved lamellar.
On {111}, rare.
Synthetic material UO2.03

Type Occurrence of Uraninite

Relationship of Uraninite to other Species

Forms a series with Thorianite (see here)
Member of:
Other Members of Group:
4.DL.05Aeschynite Group
7.16.2Schoepite(UO2)8O2(OH)12 · 12H2O
7.16.3ParaschoepiteUO3 · (2-x)H2O
7.16.4Metaschoepite(UO2)8O2(OH)12 · 10H2O
7.16.6Studtite(UO2)O2(H2O)2 · 2H2O
7.16.7IanthiniteU24+(UO2)4O6(OH)4 · 9H2O
7.16.8CompreignaciteK2(UO2)6O4(OH)6 · 7H2O
7.16.10RoubaultiteCu2O2(UO2)3(CO3)2(OH)2 · 4H2O
7.16.11BecquereliteCa(UO2)6O4(OH)6 · 8H2O
7.16.12RameauiteK2Ca(UO2)6O6(OH)4 · 6H2O
7.16.13AgrinieriteK2Ca[(UO2)3O3(OH)2]2 · 5H2O
7.16.14ProtasiteBa(UO2)3O3(OH)2 · 3H2O
7.16.15BillietiteBa(UO2)6O4(OH)6 · 8H2O
7.16.16BauranoiteBaU2O7 · 4-5H2O
7.16.17Metacalciouranoite(Ca,Na,Ba)U2O7 · 2H2O
7.16.18Calciouranoite(Ca,Ba,Pb,K,Na)U2O7 · 5H2O
7.16.24FourmarieritePb1-xO3-2x(UO2)4(OH)4+2x · 4H2O
7.16.25Richetite(Fe3+,Mg)xPb2+8.6(UO2)36O36(OH)24 · 41H2O
7.16.26CuritePb3+x[(UO2)4O4+x(OH)3-x]2 · 2H2O
7.16.27MasuyitePb(UO2)3O3(OH)2 · 3H2O
7.16.28VandendriesscheitePb1.6(UO2)10O6(OH)11 · 11H2O
7.16.29MetavandendriesscheitePbU7O22 · nH2O
7.16.30SayritePb2(UO2)5O6(OH)2 · 4H2O
7.16.31WölsendorfitePb7(UO2)14O19(OH)4 · 12H2O
7.16.32ClarkeiteNa(UO2)O(OH) · nH2O

Other Names for Uraninite

Name in Other Languages:

Other Information

Health Risks:
Contains uranium - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Avoid prolonged exposure in proximity of the body. Store away from inhabited areas.

References for Uraninite

Reference List:
Klaproth, M.H. (1797) Chemische Untersuchung des Uranerzes, Beiträge zur chemischen Kenntniss der Mineralkörper, Zweiter Band, Rottmann Berlin, 197-221.

Hillebrand (1893) USGS Bulletin 113: 37.

Goldschmidt, Thomassen (1923) Vidensk. Selsk. Skr. Mat.-nat. Kl.: 2.

Aubel (1927) C.R.: 185: 586.

Parsons (1932) Univ. Toronto Stud., Geol. Ser.: 32: 17.

Ellsworth (1935) American Journal of Science: 9: 127.

Shaub, B.M. (1938) The occurrence, crystal habit and composition of the uraninite from the Ruggles Mine, near Grafton Center, New Hampshire. American Mineralogist: 23: 334-341.

Palache, C., Berman, H., Frondel, C. (1944) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 611-620.

Rundle, R.E., Baenziger, N.C., Wilson, A.S., McDonald, R.A. (1948) The Structures of the Carbides, Nitrides and Oxides of Uranium1. Journal of the American Chemical Society: 70: 99-105.

(1958) US Geological Survey Bulletin 1064: 11-47.

Kenna, B.T., Kuroda, P.K. (1964): Technetium in nature. Journal of Inorganic and Nuclear Chemistry: 26(4): 493-499.

Haji-Vassiliou, A. (1974) Uranium mineralization - Uraninite. Mineralogical Record: 5: 79.

Snetsinger, K.G., Polkowski, G. (1977) Rare accessory uraninite in a Sierran granite. American Mineralogist: 62: 587-589.

Finch, R.J., Ewing, R.C. (1992) The corrosion of uraninite under oxidizing conditions. Journal of Nuclear Materials: 190: 133-156.

Pearcy, E.C., Prikryl, J.D., Murphy, W.M., Leslie, B.W. (1994) Alteration of uraninite from the Nopal I deposit, Peña Blanca District, Chihuahua, Mexico, compared to degradation of spent nuclear fuel in the proposed U.S. high-level nuclear waste repository at Yucca Mountain, Nevada. Applied Geochemistry: 9: 713-732.

Greenwood, N.N., Earnshaw, A. (1997): Chemistry of the Elements. Butterworth–Heinemann.

Abdelouas, A., Lutze, W., Nuttall, H.E. (1999) Oxidative dissolution of uraninite precipitated on Navajo sandstone. Journal of Contaminant Hydrology: 36: 353-375.

Alexandre, P., Kyser, T.K. (2005) Effects of cationic substitutions and alteration in uraninite, and implications for the dating of uranium deposits. The Canadian Mineralogist: 43: 1005-1017.

Fayek, M., Utsunomiya, S., Pfiffner, S.M., White, D.C., Riciputi, L.R., Ewing, R.C., Anovitz, L.M., Stadermann, F.J. (2005) The application of HRTEM techniques and nanosims to chemically and isotopically characterize Geobacter Sulfurreducens surfaces. The Canadian Mineralogist: 43: 1631-1641. [bioprecipitation of uraninite]

Plášil, J. (2014) Oxidation–hydration weathering of uraninite: the current state-of-knowledge. Journal of Geosciences: 59: 99-114.

Alexandre, P., Peterson, R., Joy, B. (2015): Sector zoning in uraninite. The Canadian Mineralogist: 53 (in press); (2016) (Los Alamos National Laboratory) (2016) (Los Alamos National Laboratory) (2016) (Los Alamos National Laboratory) (2016) (Los Alamos National Laboratory) (2016) (Los Alamos National Laboratory) (2016)

Internet Links for Uraninite URL:
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Localities for Uraninite

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