Assertion: opal | /r/HasProperty | gemstone
Facets:
value: with an iridescent quality
type: OTHER
Source sentences:
text: An opal is a 'gemstone' - that is, a mineral valued for its beauty.
text: Opals are a gemstone with an iridescent quality.
text: The Opal is a gemstone that brings through its play of colors, joy and serenity.