Common Radioactive Minerals
| Element | Mineral | Composition | Color and habit | Mode and areas of occurence |
| Thorium | Monazite | (Ce, La, Di) PO4 with small percentages of ThSiO4, usually 3-9% | Small red, brown, reddish, or brownish crystals | Accessory mineral in granites, gneisses, aplites, and pegmatites, but commercially valuable occurrences are mostly placer deposits. Placers in the Carolinas, Florida, and Idaho are mined; famous placer deposits of monazite occur in Brazil and Travancore, India, which until 1945 supplied two-fifths of the world's monazite. Important vein deposits found since 1950 in Idaho; in California with rare earths; and in South Africa, which is now a major source. |
| Thorianite | ThO2 with varying amounts of UO2 and UO3 | Black to brownish gray; greasy luster; looks much like uraninite | In pegmatites, granites, etc., and placers. Became commercial source of thorium in 1955 from placers in Madagascar. | |
| Thorite and uranothorite | ThSiO4 with possible small percentages of uranium | Usually black, sometimes orange-yellow; square crystals | In granites, pegmatites, etc., and placers. Has been found in pegmatites in Norway, Madagascar, Hybla, Ontario, North Carolina. Veins in Idaho and California. In placers in New Zealand, California. | |
| Uranium | Uraninite (pitchblende) | Complex oxide of U, Pb, Ra, and other metals, including thorium and the rare earths | Black, massive mineral with greasy, or pitch
like, luster; rarely in crystals Secondary uranium minerals such as gummite, carnotite, torberhite, autunite, tyuyamunite, etc., usually associated with it |
The most important uranium ore. Found in pegmatites and granites, and in veins with silver, lead, copper, etc. One of the largets deposits is at Great Bear Lake, Canada, where uraninite occurs with native silver and other minerals in veins, shear zones, folded sediments, and volcanics intruded by pre-Cambrian granite. In the Colorado Front Range, Gilpin County, Colo., Marysvale, Utah, and western Montana, gold-silver-quartz-pyrite veins carry uraninite. Important European vein deposits of uraninite are in Cornwall, England, Czechoslovakia, and Saxony, where veins carry silver. Greatest deposits in world are in Katanga Basin of Belgian Congo, where uraninite and its alteration product, gummite, occur in veins associated with copper deposits in faulted and crumpled limestones. Madagascar deposits are in pegmatites. Recent production from veins in Beaver Lodge area, Saskatchewan. Important new vein deposits in Cochetopa district, Colo.; western Montana; Australia. Important placer deposits in gold-bearing conglomerates at Blind River, Ontario. Recently found in sedimentary rocks in copper-uranium deposits of southern Utah, northern Arizona, and Australia; near LaSal, Utah; in sandstone and limestone in Laguna-Grants area, N. Mex. |
| Davidite | Rare earth-iron-titanium oxide; 7-10% U3O8 | Angular, irregular masses; brown to black; glossy to submetallic luster | Became significant in 1951 when found at Radium Hill, Australia, in gneisses and veins with ilmenite. | |
| Gummite | Doubtful | Yellow to brown, massive or in rounded or flattened pieces with greasy luster | Alteration product of uraninite and commonly associated with it. Abundant at Katanga, Belgian Congo, and in Mitchell County, N.C. | |
| Carnotite | Approximately K2O•2UO3 •V2O5•2H2O | Secondary mineral. Yellow crystalline powder or earth masses found in sandstones; often associated with fossil logs or bones and other secondary minerals | Found and mined in large quantities in southwestern Colorado, Utah, and New Mexico, where ore is major source of uranium in the United States. Important new deposits in Black Hills, S. Dak., in Wyoming and Ferghana Basin, U.S.S.R. Also obtained from South Australia, Katanga, Belgian Congo, and Pennsylvania. Carnotite and uraninite are chief ores of uranium. | |
| Torbernite | Cu(UO2)2)P2 O8•12H2O | Secondary mineral. Emerald green; square tabular crystals or micaceous aggregates | Occurs associated with autunite and other uranium minerals, with uranite in Belgian Congo and Czechoslovakia; occurs in North and South Australia, Cornwall, England; with tyuyamunite in Turkestan, U.S.S.R. Also in the copper-uranium deposits of Utah and Arizona. | |
| Autunite | Ca(UO2)2As2 O8•8H2O | Secondary mineral. Sulfur yellow; square tabular crystals or micaceous aggregates | Associated with other uranium minerals in Czechoslovakia, Turkestan, South Africa, northern Portugal, Cornwall, and South Australia. In the United States occurs sparingly in pegmatite in Connecticut; at Philadelphia; in mica mines of Mitchell County, N.C.; Black Hills, S. Dak.; Utah; and New Mexico. Important new deposits associated with uranophane, carnotite in Karnes City, Tex., in sedimentary rocks. On Spokane Indian Reservation, Wash., at contact of intrusives and argillite. | |
| Tyuyamunite | CaO•2UO3•K2 O5•H2O | Similar to carnotite but with slightly more greenish color | Ore in southeastern Turkestan, U.S.S.R., and important constituent at Laguna-Grants, N. Mex. | |
| Uranophane | CaO•2UO3•2SiO 2•6H2O | Slightly lighter color than autunite | Association similar to autunite and torbernite. An ore mineral at Grants, N. Mex. Important in sandstone in Wyoming. Common noncommercial mineral in granites and pegmatites in Georgia and New Hampshire. | |
| Uranium, columbium, and rare earths | Euxenite, samarskite, brannerite, betafite, pyrochlore, fergusonite, etc. | Primary oxides of Ca or Na and varying amounts of uranium, thorium, titanium, columbium, tantalum, and the rare earths | All are black to yellow brown | Occur along with other minerals typical of pegmatites, veins, contact metamorphic areas, and some placers. Brannerite is an ore at Blind River, Ontario, and Idaho placers. Pyrochlore and betafite at Hybla, Ontario, Oka, Quebec, and similar localities. Madagascar pegmatites are rich in fergusonite. |
| Columbite-tantalite | Variable from (Fe, Mn)O•Cb2O5 to (Fe, Mn)O•Ta2O5; 0-0.6% U3O8 | Black to reddish-brown crystals and masses | Principal columbium-tantalum minerals. In same associations as the above minerals. In Belgian Congo, Nigeria as ore. Often with beryl, as in Brazil. | |
| Potassium | Sylvite Carnallite | KCl KCl•MgCl2•6H2O |
Colorless, white, or red crystalline masses | Saline deposits in sediments. |
| Orthoclase and microcline feldspars | KAlSi3O8 | White, pink, gray, or green crystalline masses | Most abundant constituents of acid igneous rocks and pegmatites. | |
| Muscovite | H2KAl(SiO4)3 | Colorless, brownish, or greenish mica | Common constituent in all acid igneous rocks and pegmatites. | |
| Alunite | K2Al6(OH) 12SO4 | White, grayish, reddish masses with fibrous, granular, or earthy texture | Alteration product of acid volcanic rocks. |