Assertion: quality obsidian | /r/CapableOf | form below the ground surface
Facets:
value: often
type: TEMPORAL
value: around volcanic vents
type: LOCATION
Source sentences:
text: However, the best quality obsidian often forms below the ground surface around volcanic vents.
text: However, the best quality obsidian often forms below the ground surface around volcanic vents.
text: However, the best quality obsidian often forms below the ground surface around volcanic vents.