About: http://webisa.webdatacommons.org/30175142

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	Many metals including copper and copper alloys are known to form such native oxides on exposure to ordinary air.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com