About: http://webisa.webdatacommons.org/422161191

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	As with the grinding of other items such as knives, the implement is held against the face of a rapidly revolving grindstone, originally made of natural sandstone, but later was of a man-made abrasive composite material.
http://www.w3.org/ns/prov#wasQuotedFrom	hrionline.ac.uk