Mineraller ve özellikleri Andaluzit General Andalusite Information Chemical Formula: Al2SiO5 = Al[6]Al[5]OSiO4 Composition: Molecular Weight = 162.05 gm Aluminum 33.30 % Al 62.92 % Al 2 O 3 Silicon 17.33 % Si 37.08 % SiO 2 Oxygen 49.37 % O ______ ______ 100.00 % 100.00 % = TOTAL OXIDE Empirical Formula: Al 2SiO 5 Environment: Metamorphosed peri-aluminous sedimentary rocks. Name Origin: Named after its locality. Synonym: Chiastolite ICSD 24275 PDF 39-376 Andalusite Crystallography Axial Ratios: a:b:c =0.986:1:0.7037 Cell Dimensions: a = 7.79, b = 7.9, c = 5.56, Z = 4; V = 342.17 Den(Calc)= 3.15 Crystal System: Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pnnm X Ray Diffraction: By Intensity(I/I o): 5.54(1), 2.77(0.9), 4.53(0.9), Physical Properties of Andalusite Cleavage: [110] Distinct, [100] Indistinct, [010] Poor Color: Dark green, Gray, Brown, Red, Green. Density: 3.13 - 3.17, Average = 3.15 Diaphaniety: Transparent to translucent Fracture: Splintery - Thin, elongated fractures produced by intersecting good cleavages or partings (e.g. hornblende). Habits: Blocky - Crystal shape tends to be equant (e.g. feldspars)., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Euhedral Crystals - Occurs as well-formed crystals sho wing good external form. Hardness: 6.5-7 - Pyrite-Quartz Luminescence: None. Luster: Vitreous (Glassy) Streak: white Optical Properties of Andalusite Optical Data: Biaxial (-), a=1.629-1.64, b=1.633-1.644, g=1.638- 1.65, bire=0.0090-0.0100, 2V(Calc)=80-84, 2V(Meas)=48-68. Dispersion r > v.