What is the Average grain size of basalt?

The average grain size of basalt typically ranges from 0.5 to 1 millimeter, as it is a fine-grained volcanic rock. This small grain size results from the rapid cooling of lava during volcanic eruptions, which inhibits the growth of large crystals. However, some basalt may exhibit slightly larger grains in specific contexts, such as in porphyritic basalt where larger phenocrysts are embedded in a finer matrix. Overall, basalt is characterized by its relatively uniform and small grain texture.