Examples of igneous, metamorphic, and sedimentary rocks
Igneous Rock (granodiorite).
Note how the crystals in this rock interlock with each other.
More igneous features-- click here!
Metamorphic Rock (gneiss).
This rock also displays an interlocking crystalline texture, but also exhibits a pronounced banding.
This banding in metamorphic rocks is called foliation.
Sedimentary Rock (sandstone and shale).
On close inspection, most sedimentary rock shows a granular texture--because it is made of particles (grains) of pre-existing rock. Because the grains are deposited on the earth's surface, they form layers, called bedding. Notice how regular the beds in the above photograph are when compared to the foliation in the metamorphic rock.
Back to Week 1.