Assertion: onyx | /r/HasProperty | layered stone
Facets:
value: with a white upper layer
type: OTHER
value: with a black base
type: OTHER
Source sentences:
text: Onyx is a layered stone with a black base and a white upper layer.
text: Onyx - a layered Chalcedony with black and white parallel bands, or a wide band of solid black.
text: Onyx is a layered stone with a black base and a white upper layer.