Assertion: chrysoprase | /r/ObjectUse | used as rough material
Facets:
value: in the production of carved gemstones
type: PURPOSE
Source sentences:
text: Chrysoprase, considered by some people to be the most valuable variety of chalcedony, has been used as the rough material in the production of carved gemstones -- both cameos and intaglios -- since at least the days of the Roman Empire.