Allanite-(La)

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 brownMore details...