1. Rocks and minerals
How are they formed?

2. THREE TYPES OF ROCKS
Igneous
Sedimentary
Metamorphic

3. Igneous
Rocks formed from magma that has cooled and solidified

4. 1. Intrusive (or plutonic)
Formed by slow cooling of magma in Earth’s crust
Made of very large crystal that are visible to the naked eye
Eg. gabbro

5. 2. Extrusive (or volcanic)
Formed when a volcano erupts and the magma cools with the air or water
Cools rapidly
Made of microscopic crystals
Eg. obsidian

6. 3. Porphyritic Undergoes two cooling phases Slow: in Earth’s crust
Rapid: pushed out with magma, cools on surface
Large and small crystals
Eg. granite

7. Sedimentary
rocks formed by sedimentation (rocks broken into pieces) of material at the Earth’s surface and in bodies of water
sediments formed by erosion: the action of water, wind and glaciers
fragmented then deposited
over time, these fragments are compacted and cemented

8. Sedimentary
Eg. limestone, sandstone

9. SEDIMENTARY

10. metamorphic
Already formed igneous, sedimentary or metamorphic rock undergoes change
Transformed by heat and pressure
Occurs deep in Earth’s crust
Eg. slate, quartz, marble

11. The rock cycle

12. Rock or mineral? Rocks Blend of various minerals
Different sized and kinds of grains
Minerals
Pure, natural substance

13. Identifying minerals Magnetic Metallic ( lustre) Streak (colour)
Hardness
Density