General Information:
Chemical Formula:
(K,Na)(Mg,Fe++)2(Al,Fe+++)3(Si,Al)12O30
Composition:
(Molecular Weight = 1,015.74 gm)
Potassium 2.89 % K
Sodium 0.57 % Na
Magnesium 3.59 % Mg
Aluminum 13.95 % Al
Iron 6.87 % Fe
Silicon 24.89 % Si
Oxygen 47.25 % O
Empirical Formula:
K0.75Na0.25Mg1.5Fe2+0.5Al2.25Fe3+0.75Si9Al3O30
IMA Status:
Approved IMA
Physical Properties:
Cleavage:
None
Color:
brown, green, dark blue, or black.
Density:
2.62 - 2.64, Average = 2.63
Diaphaniety:
Translucent to Opaque
Hardness:
5-6 - Between Apatite and Orthoclase
Luster:
Vitreous (Glassy)
More details...