General Information:
Chemical Formula:NaCa2(Fe++4Fe+++)Si6Al2O22(OH)2
Composition:(Molecular Weight = 990.86 gm)Sodium 2.32 %
NaCalcium 8.09 %
CaAluminum 5.45 %
AlIron 28.18 %
FeSilicon 17.01 %
SiHydrogen 0.20 %
H Oxygen 38.75 %
O Empirical Formula: NaCa2Fe2+4Fe3+(Si6Al2O22)(OH)2
Environment:Nepheline-syenite rocks.
IMA Status:Approved IMA 1978
Locality:Dungannon, Hastings Co., Ontario, Canada.
Name Origin:Named after its locality.
Physical Properties: Cleavage:[110] Perfect, [110] Perfect
Color:dark green or black.
Density:3.17 - 3.59, Average = 3.38
Diaphaniety:Transparent to translucent
Habits:Tabular - Form dimensions are thin in one direction., ,
Hardness:6 - Orthoclase
Luminescence:Non-fluorescent.
Luster:Vitreous (Glassy)
Streak:greenish gray
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