Answer:
They all are made of minerals. ... No, an igneous rock has to be under extreme heat and pressure if above the Earth's surface before it can change into a metamorphic rock. There is not extreme heat and pressure in a classroom.
A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition and the way in which it is formed. Rocks are usually grouped into three main groups: igneous rocks, metamorphic rocks and sedimentary rocks.
