Mineraller ve özellikleri Topaz General Topaz Information Chemical Formula: Al2SiO4(F,OH)2 Composition: Molecular Weight = 182.25 gm Aluminum 29.61 % Al 55.95 % Al 2 O 3 Silicon 15.41 % Si 32.97 % SiO 2 Hydrogen 0.50 % H 4.45 % H 2 O Oxygen 43.02 % O Fluorine 11.47 % F 11.47 % F - % F -4.83 % -O=F 2 ______ ______ 100.00 % 100.00 % = TOTAL OXIDE Empirical Formula: Al 2(SiO 4)F 1.1(OH)0.9 Environment: Pegmatites and high temperature quartz veins. Cavities in granites and rhyolites. IMA Status: Valid Species (Pre-IMA) Locality: Topasos Island in the Red Sea. Link to MinDat.org Location Data. Name Origin: Named after its locality. Synonym: Pycnite - yellowish white- Topaz Crystallography Axial Ratios: a:b:c =0.4943:1:0.9545 Cell Dimensions: a = 4.35, b = 8.8, c = 8.4, Z = 4; V = 321.55 Den(Calc)= 3.76 Crystal System: Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pbnm X Ray Diffraction: By Intensity(I/I o): 2.937(1), 3.195(0.65), 3.369(0.6), Forms: Mouse Dbl Clk - Start-Stop Rotation RMB - Cycle Display Modes Drag1 - Manipulate Crystal Drag2 - Resize Keyboard S - Stereo I - Indicies - Start-Stop Rotation F - Fit to Screen M - Menu Help on Above Forms: [ 0 1 0] [ 0 2 1] [ 1 1 1] [ 0 1 1] [ 1 1 2] [ 1 2 0] [ 1 1 0] [ 0 0 1] Warning: this large pop-up is very compute intensive and may not work well with some computers. Physical Properties of Topaz Cleavage: [001] Perfect Color: Colorless, Pale blue, Yellow, Yellowish brown, Red. Density: 3.5 - 3.6, Average = 3.55 Diaphaniety: Transparent Fracture: Brittle - Uneven - Very brittle fracture producing uneven fragments. Habits: Crystalline - Coarse - Occurs as well-formed coarse sized crystals., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Massive - Granular - Common texture observed i n granite and other igneous rock. Hardness: 8 - Topaz Luminescence: Fluorescent, Short UV=golden yellow, Long UV=cream. Luster: Vitreous (Glassy) Streak: white Optical Properties of Topaz Gladstone-Dale: CI meas= 0.146 (Poor) - where the CI = (1- KPDmeas/KC) CI calc= 0.193 (Poor) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.1653,KPDmeas= 0.1751,KC= 0.2049 Optical Data: Biaxial (+), a=1.606-1.629, b=1.609-1.631, g=1.616- 1.638, bire=0.0090-0.0100, 2V(Calc)=58-68, 2V(Meas)=48-68. Dispersion noticeable, r > v. Pleochroism (x): colorless. Pleochroism (y): colorless. Pleochroism (z): colorless. Topaz Classification Dana Class: 52.3.1.1 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O (52.3)with cations in [6] coordination only (52.3.1)Dana Group 52.3.1.1 Topaz Al2SiO4(F,OH)2 Pbnm 2/m 2/m 2/m Strunz Class: VIII/B.02-70 VIII - Silicates VIII/B - Nesosubsilicates, with anions unfamiliar to tetraheders, cations of octahedral and tetrahedral orientation [4/6] VIII/B.02 - Disthene series VIII/B.02-10 Sillimanite Al2SiO5=Al[6]Al[4]OSiO4 P nma 2/m 2/m 2/m VIII/B.02-20 Andalusite Al2SiO5=Al[6]Al[5]OSiO4 Pnnm 2/m 2/m 2/m VIII/B.02-30 Kanonaite (Mn,Al)AlSiO5 Pnnm 2/m 2/m 2/m VIII/B.02-40 Kyanite Al2SiO5=Al[6]Al[6]OSiO4 P1 1 VIII/B.02-50 Mullite Al4Si2O10 Pbam 2/m 2/m 2/m VIII/B.02-60 Yoderite Mg2(Al,Fe)6Si4O18(OH)2 P 2 1 2 VIII/B.02-70 Topaz Al2SiO4(F,OH)2 Pbnm 2/m 2/m 2/m