Basalt is usually dark grey to black in colour, due to its high content of augite or other dark-coloured pyroxene minerals, but can exhibit a wide range of shading. Some basalts are quite light-coloured due to a high content of plagioclase, and these are sometimes described as leucobasalts.

Basalt is known for its dark color, typically ranging from black to dark gray, and its fine-grained texture.

Basalt is usually black or dark gray and relatively featureless. It is composed of mineral grains which are mostly indistinguishable to the naked eye. Basalt may also contain volcanic glass. Basalt may contain phenocrysts (larger crystals within fine-grained groundmass) and vesicules (holes that were filled by volcanic gases).