1. Three Classes of Rocks: Igneous, Sedimentary, Metamorphic
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Three Classes of Rocks:
Igneous, Sedimentary, Metamorphic

2. Rocks are made up of Minerals

3. Rock Definition A naturally occurring mixture of one or more minerals
e.g, marble, granite, sandstone, limestone

4. Three Classes of Rocks
Igneous
Sedimentary
Metamorphic

5. Three Types of Rocks

6. Igneous Rocks
Igneous rocks are formed from magma (hot molten rock inside the earth). It becomes rock by the solidification of magma.
Granite

7. Two Types of Igneous Rocks
Extrusive igneous rocks form from lava (magma on the surface) cooling on the earths surface
Intrusive igneous rocks form when magma cools and hardens underneath the surface (i.e., below ground)

8. Igneous Rocks

9. Igneous Rock Texture
Intrusive rocks such as granite are coarse grained (can easily see the grains with the unaided eye)
Extrusive igneous rocks such as basalt are glassy or fine grained

10. Sedimentary Rocks
Sedimentary rocks are formed when small pieces of rock are carried by wind or water and settle or sink down on to rocks below them. The pressure of the layering of these sediments forms sedimentary rocks. That is why you see ‘layers’ in these rocks

11. Sedimentary rocks can be formed by…
Fragments of rocks and shells
Living material, decay of plant matter
Salts that the water dissolves from rocks

12. Metamorphic Rocks Metamorphic = Change form
Metamorphic rocks are formed by the transformation or changing of previously-existing rocks from increased temperature and pressure. These rocks start as iggi – sedi – or metti.