Hot molten rock, also known as LAVA, is a type of molten rock that is formed when magma from the Earth's mantle rises to the surface. It is composed of various minerals and gases and is usually very hot, reaching temperatures of up to 1, 200 degrees Celsius. LAVA is an important part of the Earth's geology, as it is responsible for the formation of many landforms such as volcanoes, islands, and mountains.