General Information:
Chemical Formula:Ca(La,Ce)(Fe++,Mn++)(Al,Fe+++)2(SiO4)(Si2O7)O(OH)
Composition:(Molecular Weight = 596.56 gm)Calcium 6.72 %
CaLanthanum 17.46 %
LaCerium 5.87 %
CeManganese 2.30 %
MnAluminum 6.78 %
AlIron 11.70 %
FeSilicon 14.12 %
SiHydrogen 0.17 %
H Oxygen 34.87 %
O Empirical Formula: CaLa0.75Ce0.25Fe2+0.75Mn2+0.25Al1.5Fe3+0.5(SiO4)(Si2O7)O(OH)
IMA Status:Not IMA Approved
Locality:TL: Russia, Karelia
Name Origin:Named after the Scottish mineralogist, T. Allan (1777-1833).
Physical Properties: Cleavage:[001] Imperfect, [100] Imperfect
Color:brown or black.
Density:3.3 - 4.2, Average = 3.75
Diaphaniety:Translucent to opaque
Habits:Massive - Granular - Common texture observed in granite and other igneous rock., Disseminated - Occurs in small, distinct particles dispersed in matrix.,
Hardness:5.5 - Knife Blade
Luminescence:None.
Luster:Vitreous - Greasy
Streak:grayish brown
More details...
