Thorianite
Encyclopedia
Thorianite is a rare mineral, originally discovered by Ananda Coomaraswamy
in 1904 as uraninite, but recognized as a new species by Wyndham R. Dunstan. It was so named on account of its high percentage of thorium
(about 70% ThO2); it also contains the oxides of uranium
, lanthanum
, cerium
and didymium
(praseodymium
and neodymium
). Helium
is present, and the mineral is slightly less radioactive than pitchblende but harder to shield due its high energy gamma rays. It is more common in the alluvial gem-gravels of Sri Lanka
, where it occurs mostly as water worn, small, heavy, black, cubic crystals. The largest crystals (sizes usually up to around 1.5 cm; very rare are sizes greater than 2.5 cm; largest is 6 cm and 2.2 kilos) came from Madagascar
.
Thorianite and uraninite
form a complete solid solution
series in synthetic and natural material. The division between the two species is at Th:U = 1:1 with U up to 46.50% and Th 45.3% to 87.9%. Rare earths, chiefly Ce, substitute for Th in amounts up to 8% by weight. Ce is probably present as Ce4+. Complete series is known in synthetic material between CeO2 - PrO2 - ThO2 - UO2. Small amounts of Fe3+ and Zr also may be isomorphous with Th. Pb present is probably radiogenic.
Ananda Coomaraswamy
Ananda Kentish Coomaraswamy was a Ceylonese philosopher and metaphysician, as well as a pioneering historian and philosopher of Indian art, particularly art history and symbolism, and an early interpreter of Indian culture to the West...
in 1904 as uraninite, but recognized as a new species by Wyndham R. Dunstan. It was so named on account of its high percentage of thorium
Thorium
Thorium is a natural radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 and named after Thor, the Norse god of thunder....
(about 70% ThO2); it also contains the oxides of uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
, lanthanum
Lanthanum
Lanthanum is a chemical element with the symbol La and atomic number 57.Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table and is the first element of the lanthanide series. It is found in some rare-earth minerals, usually in combination with cerium and...
, cerium
Cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet . Cerium is the most abundant of the rare earth elements, making up about 0.0046% of the Earth's crust by weight...
and didymium
Didymium
Didymium is a mixture of the elements praseodymium and neodymium. It is used in safety glasses for glassblowing and blacksmithing, especially when a gas powered forge is used, where it provides a filter which selectively blocks the yellowish light at 589 nm emitted by the hot sodium in the glass,...
(praseodymium
Praseodymium
Praseodymium is a chemical element that has the symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is too reactive to be found in native form, and when artificially prepared, it slowly develops a green oxide coating.The element...
and neodymium
Neodymium
Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite...
). Helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
is present, and the mineral is slightly less radioactive than pitchblende but harder to shield due its high energy gamma rays. It is more common in the alluvial gem-gravels of Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
, where it occurs mostly as water worn, small, heavy, black, cubic crystals. The largest crystals (sizes usually up to around 1.5 cm; very rare are sizes greater than 2.5 cm; largest is 6 cm and 2.2 kilos) came from Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
.
Chemistry
Based on color, specific gravity and composition three types of thorianite are distinguished:- α - thorianite
- β - thorianite
- γ - thorianite
Thorianite and uraninite
Uraninite
Uraninite is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2, but also contains UO3 and oxides of lead, thorium, and rare earth elements...
form a complete solid solution
Solid solution
A solid solution is a solid-state solution of one or more solutes in a solvent. Such a mixture is considered a solution rather than a compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the mixture remains in a single homogeneous phase...
series in synthetic and natural material. The division between the two species is at Th:U = 1:1 with U up to 46.50% and Th 45.3% to 87.9%. Rare earths, chiefly Ce, substitute for Th in amounts up to 8% by weight. Ce is probably present as Ce4+. Complete series is known in synthetic material between CeO2 - PrO2 - ThO2 - UO2. Small amounts of Fe3+ and Zr also may be isomorphous with Th. Pb present is probably radiogenic.
Varieties
- Aldanite - a variety of thorianite containing 14.9% to 29.0% UO2 and 11.2% to 12.5% PbO.
- Uranothorianite
- Thorianite Cerian
- Thorianite La bearing
Occurrence
Usually found in alluvial deposits, beach sands heavy mineral placers and pegmatites.- Sri Lanka - In stream gravels, GalleGalleGalle is a city situated on the southwestern tip of Sri Lanka, 119 km from Colombo. Galle is the capital city of Southern Province of Sri Lanka and it lies in Galle District....
district, Southern Province; BalangodaBalangodaBalangoda is a town in Sabaragamuwa Province of Sri Lanka. Its 143 km away from Colombo and 43 km away from Ratnapura. It is the one of biggest towns of the Ratnapura District which is one of the two districts belonging to Sabaragamuwa Province . According to the 2001 census Balangoda has a...
district; near Kodrugala, Sabaragamuwa Province; and from a pegmatite in Bambarabotuwa area. - IndiaIndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
- Reported from beach sands of TravancoreTravancoreKingdom of Travancore was a former Hindu feudal kingdom and Indian Princely State with its capital at Padmanabhapuram or Trivandrum ruled by the Travancore Royal Family. The Kingdom of Travancore comprised most of modern day southern Kerala, Kanyakumari district, and the southernmost parts of...
(KeralaKeralaor Keralam is an Indian state located on the Malabar coast of south-west India. It was created on 1 November 1956 by the States Reorganisation Act by combining various Malayalam speaking regions....
). - Madagascar - Found in alluvial deposits of BetrokaBetrokaBetroka is a hilly city in Anosy Region in southern Madagascar, and is the source of the Onilahy River...
and Andolobe. Also as very large crystals from Tôlanaro (Fort Dauphin)TôlanaroTôlanaro or Tolagnaro is a city in Madagascar. It is the capital of Anosy Region and of Tôlanaro District. It has a port of local importance, and a new port has been built at Ehoala...
; at Andranondambo and other localities. - RussiaRussiaRussia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
- In black sands of a gold placer on Boshogoch River, Transbaikalia, SiberiaSiberiaSiberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
; in the KovdorKovdorKovdor is a town and the administrative center of Kovdorsky District of Murmansk Oblast, Russia, mostly known by its mining industry. Population: -Economy:...
massif, Kola PeninsulaKola PeninsulaThe Kola Peninsula is a peninsula in the far northwest of Russia. Constituting the bulk of the territory of Murmansk Oblast, it lies almost completely to the north of the Arctic Circle and is washed by the Barents Sea in the north and the White Sea in the east and southeast...
; in the Yenisei Range, Siberia. - United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
- reported from EastonEaston, PennsylvaniaEaston is a city in Northampton County, Pennsylvania, United States. The population was 26,800 as of the 2010 census. It is the county seat of Northampton County....
, PennsylvaniaPennsylvaniaThe Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
; black sands in Missouri RiverMissouri RiverThe Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
, near HelenaHelena, MontanaHelena is the capital city of the U.S. state of Montana and the county seat of Lewis and Clark County. The 2010 census put the population at 28,180. The local daily newspaper is the Independent Record. The Helena Brewers minor league baseball and Helena Bighorns minor league hockey team call the...
, MontanaMontanaMontana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
; Scott RiverScott RiverThe Scott River is a river in Siskiyou County, California, United States. It is a tributary of the Klamath River, one of the largest rivers in California....
, Siskiyou CountySiskiyou County, CaliforniaSiskiyou County is a county located in the far northernmost part of the U.S. state of California, in the Shasta Cascade region on the Oregon border. Yreka is the county seat. Because of its substantial natural beauty, outdoor recreation opportunities, and Gold Rush era history, it is an important...
, CaliforniaCaliforniaCalifornia is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
; black sands in Nixon Fork and WisemanWiseman, AlaskaWiseman is a census-designated place in Yukon-Koyukuk Census Area, Alaska, United States. The population was 21 at the 2000 census.Wiseman is a small mining community in the Brooks Range. It was founded by gold miners who abandoned the Slate Creek settlement around 1919...
districts, AlaskaAlaskaAlaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
. - CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
- Reported with uraninite in a pegmatite on Charlebois Lake, east of Lake AthabascaLake AthabascaLake Athabasca is located in the northwest corner of Saskatchewan and the northeast corner of Alberta between 58° and 60° N.-History:The name in the Dene language originally referred only to the large delta formed by the confluence the Athabasca River at the southwest corner of the lake...
; Uranon variety reported from pegmatitePegmatiteA pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic....
and metesomatized zones in crystalline limestones from many locations in QuebecQuebecQuebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
and OntarioOntarioOntario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
. - South AfricaSouth AfricaThe Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
- Occurs with baddeleyiteBaddeleyiteBaddeleyite is a rare zirconium oxide mineral , occurring in a variety of monoclinic prismatic crystal forms. It is transparent to translucent, has high indices of refraction, and ranges from colorless to yellow, green, and dark brown. Baddeleyite is a refractory mineral, with a melting point of...
as an accessory in carbonatiteCarbonatiteCarbonatites are intrusive or extrusive igneous rocks defined by mineralogic composition consisting of greater than 50 percent carbonate minerals. Carbonatites may be confused with marble, and may require geochemical verification....
at PhalaborwaPhalaborwaPhalaborwa is a town situated in the Mopani district, halfway up along the length of the Kruger National Park in the Limpopo province in South Africa. The Lowveld, also known as Valley of the Olifants, has the highest winter temperatures in South Africa. The rainfall is low and the average winter...
, Eastern Transvaal. - Belgian CongoBelgian CongoThe Belgian Congo was the formal title of present-day Democratic Republic of the Congo between King Leopold II's formal relinquishment of his personal control over the state to Belgium on 15 November 1908, and Congolese independence on 30 June 1960.-Congo Free State, 1884–1908:Until the latter...
See also
- UraniniteUraniniteUraninite is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2, but also contains UO3 and oxides of lead, thorium, and rare earth elements...
- ThoriteThoriteThorite, SiO4, is a rare nesosilicate of thorium that crystallizes in the tetragonal system and is isomorphous with zircon and hafnon. It is the most common mineral of thorium and is nearly always strongly radioactive. It was named in 1829 to reflect its thorium content...
- Classification of minerals
- List of minerals