| A | B |
|---|
| the three goups of rocks are | sedimanetary, igneous, and metamorphic |
| rocks are classified based | on how they form |
| igneous rock | formed within the earth from magma or on the earth's surface from lava |
| crystal size for igneous rock formed from lava | small crystals |
| crystal size for igneous rock formed from magma | large crystals |
| examples of igneous rock formed from magma | gabbro and granite |
| examples of igneous rock formed from lava | rhyolite and basalt |
| example ofrock forming from lava that has cooled so fast that no crystals have formed | obsidian |
| color of obsidian | usually black in color |
| igneous rock that is holey due to gases trapped in it | pumice |
| pumice | a rough,holey rock that floats |
| sedimentary rock forms | from bits of rock, from water evaporating and leaving minerals behind, or from plant and animal remains |
| sedimentary rock | forms from layers of sediment being squeezed and the minerals in the rock act as the cement holding the particles together |
| sedimentary rock forming from bits of rock | are named by the size of their bits |
| conglomerate | has bits of rock the size of gravel |
| sandstone | made up of sand-sized bits |
| shale | made up of bits too tiny to be seen |
| conglomerate and sandstone have the same minerals | usually quartz |
| examples of sedimentary rock that formes when water evaporates and leaves minerals behind | gypsum and rock salt |
| rock that forms from plant and animal remains | coal |
| rock that often contains fossils | limestone |
| what a fossil is | the remains or traces of living things preserved in rocks |
| hard parts that are buried in sediment | teeth, shells, and bones |
| fossils can be | marks or prints preserved in rock |
| rock that has been changed | is called metamorphic rock |
| these two factors are responsible for changed rock | heat and pressure |
| a changed rock | is a different rock |
| limestone is changed into | marble |
| shale is changed into | slate |
| all types of rock can be changed | to make a new kind of rock |
| a metamorphic rock can even be changed into | another metamorphic rock |
| metamorphic rocks are either | banded or unbanded |
| examples of banded metamorphic rocks | slate, schist, and gneiss |
| banded means | the crystals (grains) are arranged in parallel layers or bands |
| when granite undergoes heat and pressure it becomes | gneiss(banded) |
| when shale undergoes heat and pressure it becomes | slate(banded) |
| when slate undergoes heat and pressure it becomes | schist(banded) |
| when limestone undergoes heat and pressure it becomes | marble(unbanded) |
| when sandstone undergoes heat and pressure it becomes | quartzite (unbanded) |
| rock cycle | a cycle that shows that any knid of rock can become any other kind of rock |
