Mineraller ve özellikleri Plajioklas General Plagioclase Information Chemical Formula: (Na,Ca)(Si,Al)4O8 Composition: Molecular Weight = 270.77 gm Sodium 4.25 % Na 5.72 % Na 2 O Calcium 7.40 % Ca 10.36 % CaO Aluminum 9.96 % Al 18.83 % Al 2 O 3 Silicon 31.12 % Si 66.57 % SiO 2 Oxygen 47.27 % O ______ ______ 100.00 % 101.48 % = TOTAL OXIDE Empirical Formula: Na0.5Ca 0.5Si3AlO 8 Environment: Igneous and metamorphic rocks. IMA Status: Not Approved IMA Locality: Common world wide occurrences. Link to MinDat.org Location Data. Name Origin: From the Greek plagios - "oblique" and klao - "I cleave" in allusion to the obtuse cleavage angles of the good cleavages. Plagioclase Crystallography Crystal System: Triclinic - PinacoidalH-M Symbol ( 1) Space Group: C1 Physical Properties of Plagioclase Cleavage: [001] Good, [010] Good Color: White, Gray, Bluish white, Reddish white, Greenish white. Density: 2.61 - 2.76, Average = 2.68 Diaphaniety: Transparent to translucent Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals. Habit: Massive - Granular - Common texture observed in granite and other igneous rock. Hardness: 6-6.5 - Orthoclase-Pyrite Luminescence: Non-fluorescent. Luster: Vitreous (Glassy) Streak: white Optical Properties of Plagioclase Optical Data: NCalc= 1.56 - from Gladstone-Dale relationship (KC = 0.2101) where Ncalc=Dmeas*KC+1 Plagioclase Classification Dana Class: 76.1.3.0 (76)Tectosilicate Al-Si Framework (76.1)with Al-Si frameworks (76.1.3)Plagioclase series 76.1.3.0 Plagioclase * (Na,Ca)(Si,Al)4O8 C1 1 76.1.3.1 Albite NaAlSi3O8 C1 1 76.1.3.2 Oligoclase (Na,Ca)(Si,Al)4O8 C1 1 76.1.3.3 Andesine* (Na,Ca)(Si,Al)4O8 C1 1 76.1.3.4 Labradorite* (Ca,Na)(Si,Al)4O8 C1 1 76.1.3.5 Bytownite* (Ca,Na)(Si,Al)4O8 C1 1 76.1.3.6 Anorthite CaAl2Si2O8 P1,I1 1 Strunz Class: VIII/J.07-00 VIII - Silicates VIII/J - Tectosilicates (network) without anions unfamiliar to the tetraheders VIII/J.07 - Feldspar group, Anorthoclase - Anorthite - Banalcite series