Assertion: basalt | /r/HasProperty | black
Facets:
value: in color
type: OTHER
value: usually
type: DEGREE
Source sentences:
text: Basalt is a finely granulated igneous rock, which is usually black or gray in color.
text: Basalt is usually black or dark gray and relatively featureless.
text: Basalt is dark gray or black in color and is denser than most other volcanic rocks.