Molten volcanic rock, also known as LAVA, is a hot liquid or semi-solid form of magma that is expelled from a volcano during an eruption. It is composed of various minerals and gases and can reach temperatures of up to 1, 250 degrees Celsius. LAVA is the most common type of molten volcanic rock and is responsible for the formation of many landforms such as cinder cones, LAVA domes, and shield volcanoes.