Granite and basalt are opposites on these axies for the description of igneous rocks - granite is a slow cooled quartz rich rock, basalt a rapidly cooled mafic rock. Basaltic lava flow, Idaho Basalt is the stuff of the ocean floor. It comes from fresh upwellings from the mantle. Basalts are extrusive igneous rocks rich in minerals containing magnesium and other similar metallic atoms. Most of these minerals have a dark color.
Basalts are thus dark in color.
Basalt cools rapidly as volcanic eruptions dump magma out into the air, water or inject it in little intrusions into cold rocks, crystals never have chance to grow large. A magma with at basaltic composition that cooled slowly and had a chance to grow large mineral crystals would form an intrusive igneous rock that we would call a gabbro. Granite, Acadia National Park, Maine Granite, on the other hand, is the stuff of continents. These magmas cool to produce granitic igneous rocks. Quartz and feldspar are light in color.