Assertion: cobalt | /r/ObjectUse | used to color glass
Facets:
value: from 618 ad
type: TEMPORAL
value: in the chinese tang dynasty
type: TEMPORAL
value: since the bronze age
type: TEMPORAL
Source sentences:
text: Cobalt has been used to color glass since the Bronze Age.
text: Cobalt was also used to colour glass in the Chinese Tang dynasty from 618 AD.