1. Mrs. Negrito 6th Grade Science Chapter 16 Section 1 & 2
Types of Rocks
Mrs. Negrito
6th Grade Science
Chapter 16
Section 1 & 2

2. Rocks Rock- is a solid mixture of crystals of one or more minerals.
Mineral- is naturally formed solid matter with a crystal structure.
Rocks are made up of minerals.
Composition- is the rocks make-up.

3. Rock Classification
Igneous- form when hard, liquid rock cools and hardens.
Sedimentary- form when rocks are broken down into smaller pieces that harden.
Metamorphic- rocks heated or squeezed.
Granite
Sandstone
Gneiss

4. Texture Fine-grained rocks made of small grains.
Coarse-grained rocks made of grains that are larger than a pebble.
Medium- grained texture rocks-between fine and coarse grained.

5. Texture of Rocks Coarse-grained rock Granite Fine-grained rock Basalt
Medium-textured rock
Andesite

6. Igneous Rocks Composition of lava determines type of rock.
Form when hot, liquid rock, or magma, cools to form mineral crystals. Form deep in the Earth or at sites of volcanic activity.
Extrusive- magma that reaches the surface and cools forming rocks such as: pumice,basalt, rhyolite, scoria, and obsidian,

7. Igneous Rocks, cont.
Intrusive- Magma that cools before reaching the surface. The longer it cools, the larger the crystals. Examples: Granite,and gabbro.

8. Sedimentary Rock
Form when grains of rock or sediment collect and harden into new rock.
Composition of rock depends on the sediment deposit.
Sediment is cemented together - Lithification.
Examples: Sandstone, Coquina, Shale, Rock Gypsum, Limestone, Coal, Conglomerate, Rock Salt.

9. Metamorphic Rocks
Form when rocks metamorphose or change as they are heated or squeezed.
The texture depends on how the minerals are arranged.
Rocks made of different minerals often are foliated or banded.
Non- foliated if few different minerals.
Examples:Marble and Gneiss.

10. Process that shape the Earth
Weathering- water, ice and heat break down the rock into smaller pieces or sediment.
Erosion- when grains of rock are moved from their source.
Deposition- water, ice, wind or gravity drop newly formed sediment.

11. Erosion