Thorianite

Thorianite

Infobox mineral
name = Thorianite
category =
boxwidth =
boxbgcolor =


imagesize =
caption =
formula = Thorium oxide, ThO2
molweight =
color = Dark gray, brown-black
habit = Rounded grains
system = Isometric
twinning = Penetration twins on {111} very common
cleavage = Poor/Indistinct
fracture = Irregular/Uneven,Sub-Conchoidal
mohs = 6½ - 7
luster = Resinous,Sub-Metallic
refractive =
opticalprop =
birefringence =
pleochroism =
streak = Grey, Grey green to black
gravity =
density = 9.7 g/cm3
melt =
fusibility =
diagnostic =
solubility =
diaphaneity = Translucent on thin edges
other =
var1

Thorianite is a rare mineral, [Cite book
publisher = United States Government Printing Office
last = Frondel
first = C.
title = Systematic Mineralogy of Uranium and Thorium
date = 1958] originally discovered by Ananda Coomaraswamy in 1904 as uraninite, [Cite journal
volume = Pt. 6
issue = 2
pages = 57
last = Coomaraswamy
first = A.K.
title = Uraninite
journal = Spolia Zeylanica
date = 1904] but recognized as a new species by W. R. Dunston. [Cite journal
volume = 69
pages = 510–511
last = Dunston
first = W.R.
title = The occurrence of Thorium in Ceylon
journal = Nature
date = 1904-03-31
doi = 10.1038/069510d0] 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 relatively 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.

Chemistry

Based on color, specific gravity and composition three types of thorianite are distinguished: [Cite journal
volume = 1
issue = Ist Ser
pages = 201–206
last = Kobayashi
first = M.
title = On the composition of thorianite
journal = Tohuku Imp. Univ. Sci. Repts.
date = 1912]
*α - thorianite
*β - thorianite
*γ - thorianiteThorianite and uraninite form a complete solid solution series in synthetic and natural material. [Cite journal
volume = 1
pages = 478–480
last = Palache
first = C.
coauthors = H. Berman, C. Frondel
title = Dana's System of Mineralogy
journal = John Wiley and Sons, New York
date = 1944] 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%. [Cite book
publisher = McGraw-Hill
last = Heinrich
first = E. W.
title = Mineralogy and Geology of Radioactive Raw Materials
date = 1958] Rare earths, chiefly Ce, substitute for Th in amounts up to 8% by weight. [Cite journal
volume = 1
pages = 478–480
last = Palache
first = C.
coauthors = H. Berman, C. Frondel
title = Dana's System of Mineralogy
journal = John Wiley and Sons, New York
date = 1944] [Cite journal
volume = 40
last = Graham
first = A. R.
title = CERIANITE CeO2: A NEW RARE-EARTH OXIDE MINERAL
journal = Am. Mineralogist
date = 1955] 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. [Cite journal
volume = II
issue = 6
pages = 105–107
last = Bespalov
first = M.M.
title = On discovery of a new mineral of the thorianite group [in Russian]
journal = Sovietskaya Geologiya
date = 1941]
*"Uranothorianite" [Cite web
title = Uranothorianite mineral information and data
accessdate = 2007-06-28
url = http://www.mindat.org/min-4114.html]
*"Thorianite Cerian"Cite web
title = Minerals with crystal structure determined
accessdate = 2007-06-27
url = http://sdpd.univ-lemans.fr/minknown.html#T] [Cite web
title = ICSD for WWW : Details (Thorianite Cerian)
accessdate = 2007-06-27
url = http://icsdweb.fiz-karlsruhe.de/details.php?id%5B%5D=24439&PHPSESSID=734118bb8]
*"Thorianite La bearing"

Occurrence

Usually found in alluvial deposits, beach sands heavy mineral placers and pegmatites.

*Sri Lanka - In stream gravels, Galle district, Southern Province; Balangonda district; near Kodrugala, S'abaragamuwa Province; and from a pegmatite in Bambarabotuwa area.
*India - Reported from beach sands of Travancore (Kerala). [Cite journal
volume = 88
pages = 282
last = Viswanathan
first = P.
title = Thorianite in Travancore
journal = Mineralog. Mag.
date = 1953]
*Madagascar - Found in alluvial deposits of Betroka and Andolobe. [Cite book
publisher = Augustin Challamel, éditeur, Librairie maritime et coloniale
last = Lacroix
first = A.
title = Minéralogie de Madagascar
date = 1923] Also as very large crystals from Tôlanaro (Fort Dauphin); at Andranondambo and other localities.
*Russia - In black sands of a gold placer on Boshogoch River, Transbaikalia, Siberia; in the Kovdor massif, Kola Peninsula; in the Yenisei Range, Siberia.
*United States - reported from Easton, Pennsylvania; black sands in Missouri River, near Helena, Montana; Scott River, Siskiyou County, California; [Cite journal
pages = 198
last = George
first = D'Arcy
title = Mineralogy of Uranium and Thorium Bearing Minerals
journal = USAEC Technical Information Service, Oak Ridge, Tennessee
series = RMO-563
date = 1949] black sands in Nixon Fork and Wiseman districts, Alaska. [Cite book
publisher = GS-C-195, Geological Survey
last = White
first = M. G.
title = Radioactivity of Selected Rocks and Placer Concentrates from Northeastern Alaska
date = 1952] [Cite journal
publisher = TEI-192, Geological Survey
last = White
first = M. G.
coauthors = J. M. Stevens
title = Reconnaissance For Radioactive Deposits In The Ruby-Poorman District, Ruby Quadrangle, Central Alaska,1949
date = 1953]
*Canada - Reported with uraninite in a pegmatite on Charlebois Lake, east of Lake Athabasca; [Cite book
publisher = Geological Survey of Canada
last = Lang
first = A. H.
coauthors = J. W. Griffith, H. R. Steacy
title = Canadian Deposits of Uranium and Thorium
date = 1962] Uranon variety reported from pegmatite and metesomatized zones in crystalline limestones from many locations in Quebec and Ontario. [Cite journal
volume = 40
last = Robinson
first = S. C.
coauthors = A. P. Sabina
title = Uraninite And Thorianite From Ontario And Quebec
journal = Am. Mineralogist
date = 1955]
*South Africa - Occurs with baddeleyite as an accessory in carbonatite at Phalaborwa, Eastern Transvaal. [Cite journal
volume = 40
pages = 275–282
last = Hiemstra
first = S. A.
title = Baddeleyite from Phalaborwa, Eastern Transvaal
journal = American Mineralogist
date = 1955]
*Belgian Congo [Cite journal
volume = 40
pages = C177
last = Ledoux
first = A.
title = Les roches cristallines du Kasai
journal = Soc. Geol. Belgique Annales]

ee also

*Uraninite
*Thorite

External links

* [http://www.uraniumminerals.com/UTh/Thorianite.htm Uraniumminerals.com]
* [http://www.mindat.org/min-3944.html Mindat.org]

References

*1911


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • thorianite — ● thorianite nom féminin (de thorium) Oxyde naturel d uranium et de thorium, de formule (Th,U)O2, de couleur noir de jais, cubique. thorianite [tɔʀjanit] n. f. ÉTYM. 1905, in Rev. gén. des sc., no 12, p. 585; de thor(ium), (ur)an(ium), et ite. ❖ …   Encyclopédie Universelle

  • thorianite — [thôr′ē ənīt΄] n. [< THORIA + ITE1] a grayish to black, very hard, radioactive mineral, thorium dioxide, ThO2, that is an ore of thorium …   English World dictionary

  • Thorianite — Cristaux de thorianite de Madagascar (1,6 x 1,4 x 1,3 cm) La thorianite est une espèce minérale, formée d oxyde de thorium de formule Th O2 avec des traces de U;Ce;La;Pb;TR. Variétés Aldanite une variété contenant de 14.9% à 29.0% de UO2 et 11.2% …   Wikipédia en Français

  • thorianite — /thawr ee euh nuyt , thohr /, n. a rare mineral, mainly thoria, ThO2, but also containing uranium, cerium, and other rare earth metals, occurring in small, black, cubic crystals: notable for its radioactivity and used as a minor source of thorium …   Universalium

  • thorianite — torianitas statusas T sritis chemija apibrėžtis Mineralas. formulė (Th,U)O₂ atitikmenys: angl. thorianite rus. торианит …   Chemijos terminų aiškinamasis žodynas

  • thorianite — noun Etymology: irregular from thoria Date: 1904 a strongly radioactive mineral that is an oxide of thorium and often contains rare earth elements …   New Collegiate Dictionary

  • thorianite — noun A radioactive mineral containing thorium dioxide (ThO) plus oxides of uranium, lanthanum, cerium neodymium and praseodymium in smaller quantities …   Wiktionary

  • thorianite — tho·ri·a·nite …   English syllables

  • thorianite — tho•ri•a•nite [[t]ˈθɔr i əˌnaɪt, ˈθoʊr [/t]] n. mir a rare, black, radioactive mineral, mainly thoria, ThO2, usu. found mixed with uranium, dioxide, and rare earth metals: a minor source of thorium • Etymology: 1900–05; thorian (thori ( a) + an… …   From formal English to slang

  • thorianite — /ˈθɔriəˌnaɪt/ (say thawreeuh.nuyt) noun a rare mineral, mainly thorium oxide, ThO2, but containing also uranium, cerium, etc., occurring in small, black, cubic crystals, notable for its radioactivity. {thor(ium) + ian + ite2} …  

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”