Keiviite-(Yb)

General Information:
 Chemical Formula:
(Yb,Y)2Si2O7
 Composition:
(Molecular Weight = 472.18 gm)
Yttrium 9.41 % Y 
Ytterbium 54.97 % Yb
Silicon 11.90 % Si
Oxygen 23.72 % O 
 Empirical Formula:
Yb1.5Y0.5Si2O7
 IMA Status:
Approved IMA 1987
Physical Properties:
 Cleavage:
[???] Perfect
 Color:
colorless.
 Density:
5.95
 Diaphaniety:
Transparent
 Hardness:
4-5 - Fluorite-Apatite
 Luster:
Vitreous (Glassy)
 Streak:
white
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