About: http://webisa.webdatacommons.org/216709701

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	The most traditional material is a natural stone such as sandstone or granite, but modern synthetic grinding wheels and flat sharpening stones can be manufactured in precise grades of abrasiveness according to the intended process.
http://www.w3.org/ns/prov#wasQuotedFrom	wikipedia.org