Elpidite

General Information:
 Chemical Formula:
Na2ZrSi6O15·3(H2O)
 Composition:
(Molecular Weight = 599.75 gm)
Sodium 7.67 % Na
Zirconium 15.21 % Zr
Silicon 28.10 % Si
Hydrogen 1.01 % H 
Oxygen 48.02 % O 
 Empirical Formula:
Na2ZrSi6O15·3(H2O)
 Locality:
Narsarsuk in the Julianehaab district, southern Greenland.
Physical Properties:
 Cleavage:
[???] Perfect, [???] Perfect
 Color:
brown, colorless, yellow brown, white, or light red.
 Density:
2.54
 Diaphaniety:
Transparent to translucent
 Habits:
Fibrous - Crystals made up of fibers., ,
 Hardness:
7 - Quartz
 Luminescence:
Non-fluorescent.
 Luster:
Vitreous (Glassy)
 Streak:
white
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