About: http://webisa.webdatacommons.org/398697397

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	Over time, coins tone when they are exposed to sulfur and other chemicals.
http://www.w3.org/ns/prov#wasQuotedFrom	usmint.gov