<http://schema.org/keywords>
"COPPER, free trial, LEAD, NICKEL, ZINC"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mcxcontrol.com/2015/03/23/mcx-base-metal-tips-nickel-s2865-s1874-r1888-r2895-91-9984712051/>