My periodic table poster is now available! Magnesite. Description from the source: Magnesite (Mg CO3 trig.), Steiermark, Austria. White botryoidal masses. 2,5x1,8x1,5 cm; 12 g with box. Source: Simone Citon Contributor: John Gray Acquired: 30 September, 2008 Text Updated: 1 October, 2008 Price: Trade Size: 1" Composition: MgCO3