About: http://webisa.webdatacommons.org/201844739

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	Crystals with cores rich in a metal, such as iron, but with outer zones rich in other metals, such as magnesium, tended to form when the volcano was active.
http://www.w3.org/ns/prov#wasQuotedFrom	rsc.org