My periodic table poster is now available! Topaz. Description from the source: Topaz (Al2 Si O4 (F OH)2 orth.), Perfect, transparent crystals with a bit of matrix. 2,6x2,1x1,5 cm; 10 g with box. Source: Simone Citon Contributor: John Gray Acquired: 28 January, 2009 Text Updated: 29 January, 2009 Price: Trade Size: 1" Composition: Al2SiO4(FOH)2