PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • When light moves from one transparent medium, such as air, to another transparent medium of a different refractive index, such as glass, provided it???s not moving at exactly 90 degrees to the surface, the direction that it takes through the new material changes.
http://www.w3.org/ns/prov#wasQuotedFrom
  • mindat.org