Epistolite

General Information:
 Chemical Formula:
Na5Ti+++Nb2Si4O12O5F·5(H2O)
 Composition:
(Molecular Weight = 842.05 gm)
Sodium 13.65 % Na
Titanium 5.69 % Ti
Niobium 22.07 % Nb
Silicon 13.34 % Si
Hydrogen 1.20 % H 
Oxygen 41.80 % O 
Fluorine 2.26 % F 
 Empirical Formula:
Na5TiNb2Si4O17F·5(H2O)
Physical Properties:
 Cleavage:
[001] Perfect, [110] Distinct
 Color:
white, yellowish white, gray, or light brown.
 Density:
2.65 - 2.89, Average = 2.77
 Diaphaniety:
Translucent
 Hardness:
1-1.5 - Talc or a little harder
 Luster:
Pearly
 Streak:
white
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