Mineraller ve özellikleri Anortit General Anorthite Information Chemical Formula: CaAl2Si2O8 Composition: Molecular Weight = 277.41 gm Sodium 0.41 % Na 0.56 % Na 2 O Calcium 13.72 % Ca 19.20 % CaO Aluminum 18.97 % Al 35.84 % Al 2 O 3 Silicon 20.75 % Si 44.40 % SiO 2 Oxygen 46.14 % O ______ ______ 100.00 % 100.00 % = TOTAL OXIDE Empirical Formula: Na0.05Ca0.95Al 1.95Si2.05O 8 Environment: Magmatic and metamorphic rocks. Name Origin: From the Greek, an + orthos, "not upright" in allusion to the oblique crystals. Synonym: Ab0 An100 ICSD 654 Indianite PDF 41-1486 Anorthite Crystallography Axial Ratios: a:b:c =0.635:1:1.1003 Cell Dimensions: a = 8.177, b = 12.877, c = 14.169, Z = 8; alpha = 93.166°, beta = 115.85°, gamma = 91.216° V = 1,340.29 Den(Calc)= 2.75 Crystal System: Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1,I1 X Ray Diffraction: By Intensity(I/I o): 3.2(1), 3.18(0.75), 4.04(0.6), Forms: [ 0 0 1] [ 1 0 0] [ 1 0 1] [ 0 1 0] Physical Properties of Anorthite Cleavage: [001] Perfect, [010] Good Color: Colorless, Gray, White, Red, Reddish gray. Density: 2.72 - 2.75, Average = 2.73 Diaphaniety: Transparent to Subtransparent to translucent Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. Habits: Granular - Generally occurs as anhedral to subhedral crystals in matrix., Euhedral Crystals - Occurs as well-formed crystals showing good external form., Striated - Parallel lines on crystal surface or cleavage face. Hardness: 6 - Orthoclase Luminescence: None. Luster: Vitreous (Glassy) Streak: white Optical Properties of Anorthite Optical Data: Biaxial (-), a=1.572-1.576, b=1.5785-1.5832, g=1.583- 1.588, bire=0.0110-0.0120, 2V(Calc)=78, 2V(Meas)=78. Dispersion relatively weak.