Assertion: cobalt | /r/ObjectUse | used in jewelry
Facets:
value: to create a cobalt blue pigment
type: PURPOSE
value: since ancient times
type: TEMPORAL
Source sentences:
text: Cobalt used in jewelry is often alloyed with metals such as chromium, tungsten and iron.
text: It is an element that has been used in jewelry since ancient times (mainly to create a cobalt blue pigment), and is not found isolated in nature.