Assertion: chalcedony | /r/CapableOf | occur as secondary mineral
Facets:
value: basically
type: DEGREE
value: in volcanic rocks
type: LOCATION
Source sentences:
text: Chalcedony basically occurs as a secondary mineral in volcanic rocks, representing the silica setfree by the decomposition of the various silicates deposited in cracks, forming veins, or in vesicular hollows forming amygdales.