Did you know there are three types of rock on this planet? In Rocks for Kids, you will learn all about how different kinds of rocks form. You will discover the properties and traits that make these rocks unique. And maybe you will find that being a geologist, a scientist that studies rocks, would totally rock! Your kids will learn interesting facts about sedimentary rocks, metamorphic rocks, and igneous rocks. For instance, did you know that fossils are really only found in sedimentary rocks? You wouldn't find a dinosaur bone in a slab of marble. Speaking of marble, marble is a type of metamorphic rock. Metamorphic rocks form with really high pressure and heat beneath the earth's surface. Igneous rocks actually divide further into two categories. There are intrusive (or plutonic) igneous rocks and extrusive igneous rocks. Intrusive rocks form when magma cools slowly inside the earth. An example of an intrusive igneous rock is granite. Extrusive igneous rocks form when lava cools real