Mineral Species containing Thulium (Tm)

Element Properties, Isotopic Compositions for Thulium

**Thulium (Tm) Element Properties**
Atomic Mass	168.93421
Atomic Number	69
Name Origins	Named after Thule, ancient Scandinavia.
Year Discovered	1879
Discovery Credits	Discovered by P. T. Cleve at Uppsala, Sweden.
Remarks	Silvery metal, rarest of the lanthanide group. Tarnishes in air and reacts with water, Few uses but some employed as a radiation source in portable x-ray equipment. Diagnostic tests: There are no simple diagnostic tests to identify thulium. X-ray fluorescence spectroscopy is commonly employed to identify and analyze members of the Rare-Earth group elements.
References	Emsley, J., 1991; THE ELEMENTS : Sec. Ed., Clarendon Press, Oxford, 251 p.
See Also	WebElements, ChemiCool

**Naturally Occurring Isotopes**
Symbol	Isotope Mass	Isotope Nuclide Number	Isotope Number	Natural Abundance	Half-life	Half-life Units	Decay Mode	Decay Mode MeV	Decay Mode %
Tm	168.934212	169	69	100.0000%		Stable
Tm	169.935198	170	69	0.0000%	128.6	Years	beta - EC	0.968 0.314	99.80% 0.20%

Thulium (Tm) Minerals sorted by Descending Weight Percent

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**4 Minerals containing Thulium (Tm) sorted by Descending Weight Percent**
% Tm	Mineral Name	Chemical Formula	MW
0.54 % Tm	Samarskite-(Yb) !	(Yb,Y,REE,U,Th,Ca,Fe++) (Nb,Ta,Ti)O4	312.29
0.54 % Tm	Iwashiroite-(Y) !	YTaO4	313.16
0.39 % Tm	Hingganite-(Y)	Y2([ ])Be2Si2O8(OH)2	433.65
0.13 % Tm	Yakovenchukite-(Y) !	K3NaCaY2(Si12O30)·4H2O	1,256.79

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(? - IMA Discredited Mineral Species Name)
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