Assertion: basalt | /r/HasProperty | porphyritic
Facets:
value: often
type: TEMPORAL
Source sentences:
text: Basalt has a fine-grained mineral texture due to the molten rock cooling too quickly for large mineral crystals to grow; it is often porphyritic, containing larger crystals (phenocrysts) formed prior to the extrusion that brought the magma to the surface, embedded in a finer-grained matrix.