Exfoliating Lava Stone – Use this stone to exfoliate your dead skin away! Even helps on tough foot calluses. This is a pumice stone, which is formed when lava from volcanoes flows into water. When lava and water meet, it instantly turns into stone and is perfect for a light, yet abrasive exfoliator! Pumice stones help increase blood flow and regenerate new skin cells when used all over the body.