We just learned about the metamorphic rock Slate.
Another type of igneous rock is called Pumice.
Pumice is made up mostly of volcanic glass, and it has tiny holes all through it like bubbles.
Because there are so many holes in it, pumice is very light and sometimes can even float on top of water!
Pumice is very rough to touch, so sometimes it is used to scrub the bottoms of people's feet to help scrub away old skin and make their feet soft again like a baby's feet.
(from: wikipedia - pumice)
Kid Facts - Blast from the past: Distance
