Lavastone also known as another kind of Basalt, just like andesit, is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered lavastone is black or grey, and it is mostly perforated, far different from basalt andesit