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
More details...