Assertion: opal's host rock | /r/CapableOf | form as part of the opal
Facets:
Source sentences:
text: Formed in areas of Ironstone, Boulder Opals are created when the host rock (Ironstone) forms with/as part of the opal when the gem is formed in cracks/voids within the host rock.
text: Formed in areas of Ironstone, Boulder Opals are created when the host rock (Ironstone) forms with/as part of the opal when the gem is formed in cracks/voids within the host rock.