An amazing piece of fan mail. Precious metals video: http://youtu.be/Fg2WzCzKpYU Gold Vault video: http://youtu.be/CTtf5s2HFkA More chemistry at http://www.periodicvideos.com/ Follow us on Facebook at http://www.facebook.com/periodicvideos And on Twitter at http://twitter.com/periodicvideos From the School of Chemistry at The University of Nottingham: http://bit.ly/NottChem Periodic Videos films are by video journalist Brady Haran: http://www.bradyharan.com/ A run-down of Brady's channels: http://bit.ly/bradychannels