| Term | Definition |
| Minerals | Rocks are made from these natural nonliving solid crystals . |
| Cenozoic | The most recent period of the Geologic Time Scale |
| Hardness | The property of rocks that describes how easily it can be scratched by another rock |
| Streak | The property of rocks that is the color of the powder that it leaves when it is scratched against a special plate |
| Diamond | The hardest rock on the MOH's Scale for hardness |
| Talc | The softest rock on the MOH's Scale for hardness |
| Erosion | The process where water, ice, wind, and/or gravity carries bits of rock, soil, shells, and dead organism materials from one place to another |
| Sediments | Eroded materials that settle on land or at the bottom of waterways, including lakes, river, or oceans |
| Sedimentary Rocks | Rocks formed when sediments are cemented together by pressure and clay materials, then harden |
| Fossils | The remains of living things that are found in sedimentary rocks |
| Magma | Partially melted rock UNDER the Earth's crust |
| Pumice | The type of igneous rock formed with many airholes, allowing it to float on water |
| Igneous Rocks | Rocks that are formed from cooled lava |
| Metamorphic Rocks | The type of rocks that have been changed completely as a result of heat and pressure |
| Rock Cycle | The ongoing process that changes one type of rock into another |
| Shale | The sedimentary rock from which the metamorphic rock slate may be formed |
| Limestone | The sedimentary rock from which the metamorphic rock marble may be formed |
| Quartz | The igneous rock from which the metamorphic rock gneiss may be formed |
| Precambrian | The oldest period of the Geologic Time Scale |
| Luster | The property of rocks that describes the way it reflects light |
