From publisher blurb:
This free companion product compliments Elemental Gemstones. Unlock the magical secrets of the world's metals with this free download. 23 real world metals are explored, from commonly known metals such as copper and gold, to rare and elusive ones such as duralumin and tantalum, to metals that have been practically forgotten by time such as hepatizon and tumbaga.
This product is useable in any roleplaying system, and will provide game masters and storytellers with plenty of ideas to create their own magical items. Combine with the information in Elemental Gemstones to create true relics of power!