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 %
NaMagnesium 3.59 %
MgAluminum 13.95 %
AlIron 6.87 %
FeSilicon 24.89 %
SiOxygen 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)
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