Magma and lava are words that are used in relation to rock formation. Magma refers to melted rock, that is rock in liquid form, which is found in the earth's crust. The lava on the other hand to the magma which has escaped from the earth crust and has moved to the surface via volcano vent. Thus. magma and lava both refer to molten rock, but magma refers to the molten rock that is found underneath the earth while lava refer to the molten rock that is found on the earth surface; that is the difference between them.