| A | B |
|---|
| igneous | formed by cooling and hardening of magma or lava |
| sedimentary | formed by hardening or cementing of sediments |
| metamorphic | formed when existing rocks are changed by heat and pressure |
| texture | size and arrangement of mineral crystals |
| instrusive texture | formed underground from magma that cooled slowly; large crystals; coarse |
| extrusive texture | formed above ground from lava that cooled quickly; small crystals; fine grained |
| mineral composition | the minerals found in an igneous rock; usually shows as the color of the rock |
| mafic | dark colored; low in silica; most extrusive rocks are mafic |
| felsic | light colored; low density; high silica; most intrusive rocks are felsic |
