basalt igneous rock in a hand. basalt is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase.

aggregate background big black boulder carbon cerussite close coal collection conglomerate crystal deep example formations fossil fuel generally geological geology gneiss granite grey isolated macro made mass matter metamorphic mineral mineraloid minerals mixed natural naturally nature object occurring ore pebble percent processes psilomelane raw rock rocks rough sample solid specimen stone texture white