My periodic table poster is now available! Quartz. Description from the source: Quartz (SiO2 trig.), San Luis Potosi`, Mexico. Perfect biterminated crystal. 3,5x2,5x2,1 cm; 15 g. Source: Simone Citon Contributor: John Gray Acquired: 26 September, 2008 Text Updated: 28 September, 2008 Price: Trade Size: 1.4" Composition: SiO2