Keiviite-(Y)

General Information:
 Chemical Formula:
(Y,Yb)2Si2O7
 Composition:
(Molecular Weight = 388.05 gm)
Yttrium 34.37 % Y 
Ytterbium 22.30 % Yb
Silicon 14.48 % Si
Oxygen 28.86 % O 
 Empirical Formula:
Y1.5Yb0.5Si2O7
 IMA Status:
Approved IMA
Physical Properties:
 Cleavage:
[110] Perfect, [001] Indistinct
 Color:
colorless, white, or pink brown.
 Density:
4.45
 Diaphaniety:
Transparent
 Hardness:
4-5 - Fluorite-Apatite
 Luster:
Vitreous (Glassy)
 Streak:
white
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