Igneous rocks started as molten magma or lava and then cooled to become rock. Coarse grained rocks are formed when the lava cools slowly and fine grained rocks from when it cools faster. Some examples of igneous rocks are granite and peridotite. The Hawaiian islands are made of cooled volcanic lava called basalt. One of the most popular igneous rocks is an Apache Tear.
Metamorphic rocks are rocks that have been changed by heat or pressure while forming.
Sedimentary and igneous rocks can become metamorphic rock. Slate is used in blackboards, talc in talcum power, and soapstone for carving. According to Dr. Broadhead, different types of rocks can be found in different places in North America. If you go into Northern Canada, most of the rocks you find will be igneous or metamorphic. If you go down south into the US, most of what you find on the surface is going to be sedimentary rock.