A COMBINATION OF ONE OR MORE MINERALS OR ORGANIC MATTER IS CALLED ROCK

You can classify rocks by:
Composition-the minerals and organic matter a rock contains, or the makeup of the rock
Texture- the size, shape, and positions of the grains that make up the rock

IGNEOUS ROCK

• Igneous rock is formed when hot, liquid magma cools into solid rock.

2 TYPES OF IGNEOUS ROCKS

• When lava does not reach the surface it cools very slow in chambers and yforms large crystals. This is called INTRUSIVE igneous rock. Examples are granite and diorite.
• When lava does reach the surface, it cools fast and forms small crystals. This is called EXTRUSIVE igneous rock. Examples are basalt and andesite.

SEDIMENTARY ROCI

• Sedimentary rock is formed mainly on the surface of the earth. Some of the processes include weathering, erosion, deposition, burial, and cementation

3 TYPES OF SEDIMENTARY ROCKS

• Clastic sedimentary rock- forms when sediments are buried, compacted, and cemented. Examples- mudstone, siltstone, shale and sandstone.
• Chemical- forms when water, usually sea water, evaporates. Example: halite or rock salt
• Organic-forms from the remains or fossils or once living plants and animals. Example: fossiliferous

METAMORPHIC ROCKS

• Metamorphic rocks are formed when a rock is exposed to high temperature and pressure, the crystal structures of the minerals in the rock change to form new minerals.

2 TYPES OF METAMORPHIC ROCK

• Foliated metamorphic rock- formed when pressure causes the mineral grains in a rock, which has either a foliated texture or a nonfoliated texture. Foliated metamorphic rock is when the mineral grains are arranged in planes or bands. Examples: slate and phyllite
• Nonfoliated metamorphic rock- does not have grains in planes or bands. Commonly made up of one or only a few minerals. Examples: quartzite and marble