About: http://webisa.webdatacommons.org/141243741

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	All of the above materials are expensive, however, and some of the materials such as the copper oxides and the chrome containing materials can color the glass even when used in small quantities.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com