Basalt, is a common extrusive igneous volcanic rock formed from the rapid cooling of basaltic lava exposed at.Dissolved gases come out of solution and form bubbles magma decompresses as it reaches, yet are trapped as erupted hardens grey black brown pothole before can escape. Spongy structure porous crushed and broken stones frozen gibber reg regs geology geological lavas flows clinkers scoria magmatic plain lowland plateau cinder cone hill caldera pyroclastic pyroclasts material rocks area solidified shield volcano dome andesitic rhyolite field cinematic background landscape view nature natural aerial drone overhead UHD 3840X2160.