Which rock will float in water?
Answer: When rocks are submerged in water, they tend to sink because of their weight. However, pumice is the only rock that can float on water.
Pumice rocks are igneous rocks which were formed when lava cooled quickly above ground. Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano. Pumice is vesicular or has gas pockets, or in easier terms, holes on the outside of the rock. This makes the rock less dense so it will float on water.