Assertion: obsidian | /r/HasProperty | occurring volcanic glass
Facets:
value: naturally
type: MANNER
Source sentences:
text: Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.
text: Obsidian is a naturally occurring volcanic glass.
text: Obsidian is a naturally occurring volcanic glass.
text: The Maesters, however, refer to Dragonglass as obsidian — a naturally occurring volcanic glass formed as an extrusive igneous rock.
text: The earliest manufactured mirrors were pieces of polished stone such as obsidian, a naturally occurring volcanic glass.