About: http://webisa.webdatacommons.org/248021446

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Other common impurities include oxides and other compounds of calcium, magnesium, iron, and nickel.
http://www.w3.org/ns/prov#wasQuotedFrom	science.gov