Mineraller ve özellikleri Allofan General Allophane Information Chemical Formula: Al2O3·(SiO2)1·3-2·((H2O))2·5-3 Composition: Molecular Weight = 225.11 gm Aluminum 23.97 % Al 45.29 % Al 2 O 3 Silicon 16.22 % Si 34.70 % SiO 2 Hydrogen 2.24 % H 20.01 % H 2 O Oxygen 57.57 % O ______ ______ 100.00 % 100.00 % = TOTAL OXIDE Empirical Formula: (Al 2O 3)(SiO 2) 1.3·2.5(H 2O) Name Origin: From the Greek allos - "other" and phanos - "to appear." Synonym: Protoallophane Schrotterite Allophane Crystallography Crystal System: Amorphous- No Crystals X Ray Diffraction: By Intensity(I/I o): 11(1), 3.3(0.8), 2.2(0.6), Physical Properties of Allophane Cleavage: None Color: White, Green, Blue, Yellow, Brown. Density: 1.9 Diaphaniety: Translucent Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). Habits: Encrustations - Forms crust-like aggregates on matrix., Stalactitic - Shaped like pendant columns as stalactites or stalagmites (e.g. calcite)., Botryoidal - "Grape-like" rounded form s (e.g.. malachite). Hardness: 3 - Calcite Luminescence: None. Luster: Waxy Streak: white Optical Properties of Allophane Optical Data: Isotropic, n=1.47-1.496.