General Information:
Chemical Formula:(Ca,Na)(Mg,Fe++,Fe+++)[Si2O6]
Composition:(Molecular Weight = 228.05 gm)Sodium 2.52 %
NaCalcium 13.18 %
CaMagnesium 5.33 %
MgIron 12.24 %
FeSilicon 24.63 %
SiOxygen 42.09 %
O Empirical Formula: Ca0.75Na0.25Mg0.5Fe2+0.25Fe3+0.25(Si2O6)
Environment:Characteristic mineral of alkaline rocks, particularly syenites and iron-rich metamorphic and metasomatic rocks.
IMA Status:Not IMA Approved
Locality:Common world-wide.
Name Origin:Name derived from its intermediate pyroxene composition. This is not an end-member species.
Physical Properties: Cleavage:[110] Very Good, [100] Parting
Color:dark green, black, green, pale greenish yellow, or greenish gray.
Density:3.4 - 3.6, Average = 3.5
Diaphaniety:Translucent to opaque
Habits:Fibrous - Crystals made up of fibers., Anhedral Grains - Granular minerals without the expression of crystal shapes, Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Hardness:6 - Orthoclase
Luster:Vitreous (Glassy)
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