Naujakasite

General Information:
 Chemical Formula:
Na6(Fe++,Mn)Al4Si8O26
 Composition:
(Molecular Weight = 942.15 gm)
Sodium 14.64 % Na
Manganese 1.46 % Mn
Aluminum 11.46 % Al
Iron 4.45 % Fe
Silicon 23.85 % Si
Oxygen 44.15 % O 
 Empirical Formula:
Na6Fe2+0.75Mn2+0.25Al4Si8O26
Physical Properties:
 Cleavage:
[001] Perfect, [401] Distinct, [010] Distinct
 Color:
gray, pearl white, or silver white.
 Density:
2.622
 Hardness:
2-3 - Gypsum-Calcite
 Luster:
Pearly
 Streak:
gray white
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