Group of interpenetrating twinned thorianite crystals from Ambatofotsy, Madagascar (size: 1.6 x 1.4 x 1.3 cm)
General
Category
Oxide mineral
Formula (repeating unit)
Thorium oxide, ThO2
IMA symbol
Tho[1]
Strunz classification
4.DL.05
Crystal system
Isometric
Crystal class
Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m)
Space group
Fm3m
Unit cell
a = 5.595 Å; Z = 4
Identification
Color
Dark gray, brown-black
Crystal habit
Cubic crystals, usually rounded to some degree in detrital deposits
Twinning
Penetration twins on {111} common
Cleavage
Poor/Indistinct
Fracture
Irregular to uneven, sub-conchoidal
Mohs scale hardness
6.5 – 7
Luster
Resinous, sub-metallic
Streak
Grey, grey green to black
Diaphaneity
Opaque, translucent on thin edges
Specific gravity
9.7
Optical properties
Isotropic
Refractive index
n = 2.20 – 2.35
Other characteristics
Radioactive
References
[2][3][4]
Thorianite is a rare thorium oxide mineral, ThO2.[5] It was originally described by Ananda Coomaraswamy in 1904 as uraninite,[6] but recognized as a new species by Wyndham R. Dunstan.[7] It was so named by Dunstan on account of its high percentage of thorium; it also contains the oxides of uranium, lanthanum, cerium, praseodymium and neodymium. Helium is present, and the mineral is slightly less radioactive than pitchblende,[8] but is harder to shield due to its high energy gamma rays. It is common in the alluvial gem-gravels of Sri Lanka, where it occurs mostly as water worn, small, heavy, black, cubic crystals. The largest crystals are usually near 1.5 cm. Larger crystals, up to 6 cm (2.4 in), have been reported from Madagascar.
^"Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2016-03-03. Retrieved 2011-12-10.
^Mindat.org
^Webmineral data
^Frondel, C. (1958). Systematic Mineralogy of Uranium and Thorium. United States Government Printing Office.
^Coomaraswamy, A.K. (1904). "Uraninite". Spolia Zeylanica. Pt. 6 (2): 57.
^Dunstan, Wyndham R. (1904-03-31). "The occurrence of Thorium in Ceylon". Nature. 69 (1796): 510–511. Bibcode:1904Natur..69..510D. doi:10.1038/069510d0. S2CID 4032255.
^One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Thorianite". Encyclopædia Britannica. Vol. 26 (11th ed.). Cambridge University Press. p. 878.
gravity and composition three types of thorianite are distinguished: α-thorianite β-thorianite γ-thorianiteThorianite and uraninite form a complete solid...
in the processing of uranium. List of minerals List of uranium mines Thorianite Uranium ore deposits Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols"...
thoria, it is mainly a by-product of lanthanide and uranium production. Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately...
occurs in several minerals including thorite (ThSiO4), thorianite (ThO2 + UO2) and monazite. Thorianite is a rare mineral and may contain up to about 12% thorium...
chosen name lutetium was adopted. In 1908, Ogawa found element 75 in thorianite but assigned it as element 43 instead of 75 and named it nipponium. In...
helium. This he obtained in 1911 from Welsbach's company, which processed thorianite to produce thorium for gas mantles. Helium is produced as a side product...
ZrSiO4) up to 0.4% thorium. Thorium dioxide occurs as the rare mineral thorianite. Due to its being isotypic with uranium dioxide, these two common actinide...
Ramsay in London, where he worked on the analysis of the rare mineral thorianite. He extracted and isolated a small amount of an apparently unknown substance...
Zimmerman. Thorium oxide was discovered by Friedrich Wöhler in the mineral thorianite, which was found in Norway (1827). Jöns Jacob Berzelius characterized...
used. 75 Rhenium 1908 M. Ogawa 1919 M. Ogawa Masataka Ogawa found it in thorianite in 1908, but assigned it as element 43 and named it nipponium. (Elements...
significant deposits of radioactive ores, including pitchblende, uranium and thorianite. In the ensuing 50 years, however, little to no effort was made to exploit...
engaged in mineralogical studies of Crown colonies. Here, with Dunstan, thorianite from Ceylon was described as a new mineral and he published papers on...
new radioactive element, extracted from a mineral from Ceylon, named Thorianite, and possibly, it is conjectured, the substance which renders thorium...
rutile (TiO2), pyrolusite (MnO2), cassiterite (SnO2), uraninite (UO2) and thorianite (ThO2). Baddeleyite is chemically homogeneous, but it may contain impurities...
viewpoints...a record of X-ray spectrum of Ogawa's nipponium sample from thorianite was contained in a photographic plate reserved by his family. The spectrum...
analyzing ten mineral samples from different world locations, including a thorianite that measured 2.2 billion years old. This value was ten times greater...
import a wide variety of ores including pitchblende, pyromorphite, and thorianite from foreign markets including Hungary, Canada and the United States....
Archived from the original (PDF) on 2014-03-28. Arkenstone. (2010). Thorianite specimen from Maromby Commune (near Tranomaro) Archived October 11, 2012...
Nuclide with A=292 and Neutron-Deficient Thorium Isotopes in Natural Thorianite 2011 — Upper Limits for the Existence of Long-Lived Isotopes of Roentgenium...
Global Information
Radioactive