<http://schema.org/keywords>
"COPPER, free trial, LEAD, NICKEL, ZINC"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mcxcontrol.com/2015/05/06/mcx-base-metal-tips-buy-zinc-153-40-153-65-sl-152-80-target-154-20-155/>