Nambulite

General Information:
 Chemical Formula:
(Li,Na)Mn++4[Si5O14(OH)]
 Composition:
(Molecular Weight = 612.13 gm)
Sodium 0.94 % Na
Lithium 0.85 % Li
Manganese 35.90 % Mn
Silicon 22.94 % Si
Hydrogen 0.16 % H 
Oxygen 39.21 % O 
 Empirical Formula:
Li0.75Na0.25Mn2+4Si5O14(OH)
 Environment:
Forms a series with natronambulite.
 IMA Status:
Approved IMA 1973
 Locality:
Funakozawa mine, Kitakami Mountains, Iwate Prefecture, Japan.
 Name Origin:
Named for Matsuo Nambu (1917-), mineralogist, Tohoko University, Japan.
Physical Properties:
 Cleavage:
[001] Perfect, [100] Distinct, [010] Distinct
 Color:
reddish orange brown.
 Density:
3.51
 Diaphaniety:
Transparent to Translucent
 Hardness:
6.5 - Pyrite
 Luster:
Vitreous - Adamantine
 Streak:
light yellow
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