| A | B |
|---|
| limestone | sedimentary rock made of calcium carbonate and compressed remains of plants and animals |
| chalk | sedimentary rock that contains almost pure calcium carbonate |
| sandstone | sedimentary rock made from compressed sand |
| mudstone | sedimentary rock made of compressed flaky grains of clay and mud |
| siltsone | sedimentary rock made of compressed silt |
| mudstone | sedimentary rock made of compressed flaky grains of clay and mud |
| rock salt | sedimentary rock made from compressed salt |
| granite | hard igneous rock with large crystals (intrusive) |
| basalt | hard, dense igneous rock (extrusive) |
| obsidian | smooth igneous rock with no crystals; looks like black glass (extrusive) |
| pumice | porous igneous rock made from lava foam (extrusive) |
| slate | metamorphic rock formed from mudstone |
| marble | metamorphic rock that is formed from limestone |
| quartzite | metamorphic rock formed from sandstone |
