Rocks and Minerals

By Kenrick Leiba

3 Kinds of Rock

• Igneous – rock that has melted and re-solidified.

• Sedimentary – Formed from sediments that have been compacted and cemented together.

• Metamorphic – Rock that has been changed by heat and pressures.

Layers of the Earth

Some revision on mixtures, compounds and elements

• An element has one kind of atom• A compound has two more kinds of

atoms in a fixture ratio• A mixture is mix of two or more

substances that are NOT bonded.

Most common Elements in the Earth’s crust

• OXYGEN-46.4%• SILICON-28.2%• ALUMINUM-8.2%• IRON-5.6%• CALCIUM-4.2%• SODIUM-2.4%• MAGNESIUM-2.3%• POTASSIUM-2%

Make up of the Earth’s Crust

How do Rocks differ from minerals?

• A mineral has a known chemical composition with a fixed ratio of elements. (could be an element or compound)• Rocks are made up of two or more

minerals.• Therefore a Rock is a solid mixture of

minerals the way cake is a mixture of eggs, flour, water etc.

How to identify Minerals

• Look at the following slides. Each shows several differ same samples of the same mineral.

• What feature might be most useful for identification. What problems might you encounter.

Examples of minerals

• Quartz

Sulphur

Hematite

Feldspar

Mica

Olivine

Some examples of rocks

• The following are some examples of different types of rocks.

Granite

Basalt

Most common minerals

• On the surface of continental crust: Quartz• In the whole crust: Feldspar• In the mantle: Olivine