| A | B |
|---|
| igneous rock | forms from molten rock |
| igneous rock is classified by these | origin, texture and composition |
| Extrusive igneous rock | formed from lava that erupted through the crust |
| extrusive igneous rock that make up most of the oceanic crust | basalt |
| intrusive igneous rock | formed from magma that hardens under the crust |
| intrusive igneous rock that make up most of the continental crust | granite |
| the most abundant intrusive rock | granite |
| texture | fine, coarse, glassy, prophorytic |
| formed when magma cools slowly | coarse grain |
| porphorytic texture | large and small grains |
| forms when magma cools really fast | glassy |
| what a rock is made of | composition |
| most minerals contain this | silica |
| silica | oxygen and silicon |
| low amount of silica creates | dark colored rocks |
| high amount of silica creates | light colored rocks |
| igneous rock uses | buildings, statues |
| most abundant extrusive igneous rock | basalt |
| rhyolite | fine-grained |
| obsidian | glassy, no grain |
