Sadanagaite

General Information:
 Chemical Formula:
(K,Na)Ca2(Fe++,Mg,Al,Ti)5[(Si,Al)8O22](OH)2
 Composition:
(Molecular Weight = 931.99 gm)
Potassium 3.15 % K 
Sodium 0.62 % Na
Calcium 8.60 % Ca
Magnesium 3.91 % Mg
Titanium 1.28 % Ti
Aluminum 7.96 % Al
Iron 14.98 % Fe
Silicon 18.08 % Si
Hydrogen 0.22 % H 
Oxygen 41.20 % O 
 Empirical Formula:
K0.75Na0.25Ca2Fe2+2.5Mg1.5Al0.75Ti0.25(Si6Al2O22)(OH)2
 Environment:
With lenses in titanian diopside (fassaite).
 IMA Status:
Approved IMA
 Locality:
Yuge Island, Fukui Prefecture, Japan.
 Name Origin:
Named for Ryoichi Sadanaga (1920-), professor emeritus, University of Tokyo.
Physical Properties:
 Cleavage:
[110] Perfect
 Color:
dark brown or black.
 Density:
3.3
 Diaphaniety:
Transparent to Translucent
 Hardness:
6 - Orthoclase
 Luster:
Vitreous (Glassy)
 Streak:
light brown
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