Eudialyte

General Information: Chemical Formula:Na4(Ca,Ce)2(Fe++,Mn,Y)ZrSi8O22(OH,Cl)2 (?) Composition:(Molecular Weight = 992.15 gm)Sodium 9.27 % NaCalcium 6.06 % CaCerium 7.06 % CeYttrium 0.90 % Y Zirconium 9.19 % ZrManganese 1.66 % MnIron 3.38 % FeSilicon 22.65 % SiHydrogen 0.15 % H Chlorine 1.79 % ClOxygen 37.90 % O  Empirical Formula: Na4Ca1.5Ce0.5Fe2+0.6Mn2+0.3Y0.1ZrSi8O22(OH)1.5Cl0.5 Environment:Nepheline-syenite rocks. IMA Status:Approved IMA Locality:Julianehaab district of Greenland. Name Origin:From the Greek eu - "well" and dialytos - "decomposable."Physical Properties: Cleavage:[0001] Imperfect Color:pinkish red, red, yellow, yellowish brown, or violet. Density:2.8 - 3, Average = 2.9 Diaphaniety:Transparent to Translucent Habits:Massive - Granular - Common texture observed in granite and other igneous rock., Tabular - Form dimensions are thin in one direction., Hardness:5-5.5 - Apatite-Knife Blade Luminescence:None. Luster:Vitreous (Glassy) Streak:whiteMore details...