Igneous
Metamorphic
Sedimentary
There are three types of rocks found on the Earth.
Igneous |
Metamorphic |
Sedimentary |
| Igneous Rocks are formed from magma or lava. The rate of cooling determines the size of the crystals in the rock. When the magma or lava cool fast, small crystals are formed in the rock. When the magma or lava cool slowly, large crystals are formed. Igneous rocks are the hardest rocks found. | Metamorphic Rocks are rocks that have been changed by great amounts of heat and pressure. These rocks are hard and resist weathering but they are not as hard as igneous rocks. Typically, these rocks have a smooth feeling. Early tombstones were made from limestone which was changed from sandstone. If you've looked at these old tombstones, you've noticed that the names have been weathered and are hard to read. | Sedimentary Rocks formed by pieces of other rocks that have eroded and have cemented together by pressure. These rocks have a gritty, sandy, or grainy feeling. Fossils, which are the remains of organic material embedded in rock, are found in sedimentary rock. |
Don't forget about the Rock Cycle!
