My periodic table poster is now available! Improved poster sample. This is a cleaner piece of manganese broken plate, photographed to replace the rather dirty one that's been on my poster for years. Source: Theodore Gray Contributor: Theodore Gray Acquired: 15 April, 2009 Text Updated: 15 April, 2009 Price: Donated Size: 0.5" Purity: >99% Sample Group: RGB Samples