Assertion: ore's iron | /r/HasProperty | common
Facets:
value: in iron ore
type: LOCATION
value: on the earth
type: LOCATION
Source sentences:
text: In fact, iron is so common that production generally focuses only on ores with very high quantities of it.
text: Although iron is a common element, pure iron is almost never found in nature.
text: Iron is a common mineral on the earth’s surface.
text: Iron is a common impurity in copper ores and iron ore was sometimes used as a flux, thus it is not surprising that humans mastered the technology of smelted iron only after several millennia of bronze metallurgy.