Tantalaeschynite-(Y)

General Information:
 Chemical Formula:
(Y,Ce,Ca)(Ta,Ti,Nb)2O6
 Composition:
(Molecular Weight = 499.75 gm)
Calcium 0.80 % Ca
Cerium 8.41 % Ce
Yttrium 10.67 % Y 
Tantalum 54.31 % Ta
Titanium 2.87 % Ti
Niobium 3.72 % Nb
Oxygen 19.21 % O 
 Empirical Formula:
(Y)0.6Ce0.3Ca0.1Ta1.5Ti0.3Nb0.2O6
 IMA Status:
Approved IMA 1987
 Name Origin:
Named for its composition and from the Greek for "shame," in allusion to the inability of chemists, at the time of its discovery, to separate some of its constituents.
Physical Properties:
 Cleavage:
None
 Color:
brownish black or black.
 Density:
6.39
 Diaphaniety:
Subtranslucent
 Hardness:
5.5-6 - Knife Blade-Orthoclase
 Luster:
Adamantine
 Streak:
yellowish brown
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