<http://schema.org/keywords>
"COPPER, free trial, LEAD, NICKEL, ZINC"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mcxcontrol.com/2015/03/05/mcx-base-metal-tips-lead-s2109-50-s1110-50-r1112-r2113-91-9984712051/>