Show sample as: 72-frame QuickTime VR or 360-frame QuickTime movie loop.    My periodic table poster is now available! Borrowdale graphite. The mine at Borrowdale was the first, and for a century the only, source of graphite, making it critical to the world's supply of pencils in the 1700s. Source: Andrew Goodall Contributor: Andrew Goodall Acquired: 2 April, 2009 Text Updated: 3 April, 2009 Price: Donated Size: 2" Purity: >95%