1. MINERALS
EARTH MATERIALS

2. CHEMICAL COMPOSITION OF THE LITHOSPHERE (CRUST )
The Earth’s crust is composed mainly of 8 elements…. oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, & potassium.
These elements exist in minerals, which most rocks are made of.
Identifying the common minerals is the key to understanding the composition of the crust.

3. Average Chemical Composition
of Earth’s Crust
% by mass % by volume
Oxygen (O)
Silicon (Si)
Aluminum (Al)
Iron (Fe)
Calcium (Ca)
Sodium (Na)
Magnesium (Mg)
Potassium (K)
Page 1 ESRT

4. WHAT ARE MINERALS? Minerals are made of elements Minerals are natural
Minerals are solids
Minerals are inorganic
A Minerals’ definite arrangement of atoms forms crystals
Over 3800 different minerals have been named.
A mineralogist is a scientist that studies minerals

5. Mineral Formation 1. Minerals form from magma
2. Minerals form from precipitation.
3. Pressure & Temperature
4. Hydrothermal Solutions

6. MINERALS FROM MAGMA Magma is molten material beneath Earth’s surface.
Density differences force magma upward.
Elements in the magma interact to form minerals.
The rate of cooling determines the size of the mineral crystals.
Minerals rich in iron, calcium, & magnesium form first.
Olivine & pyroxene are minerals rich in iron and magnesium. Sade` was here :D

7. MINERALS FROM SOLUTION
A solution is a mixture of a solid and a liquid.
In nature, when a solution becomes supersaturated ( overfilled ), mineral crystals begin to precipitate or “drop out” of solution.
Minerals can also form when the liquid evaporates from a solution leaving the elements behind to form crystals.
Calcite & Halite are minerals that form in this way.

8. Hydrothermal Solutions
A hydrothermal solution is a very hot mixture of water & dissolved substances.
When these solutions cool, the dissolved substances combine to form minerals.
Quartz and Pyrite form this way.

9. MINERAL GROUPS Silicate minerals 96 % of all minerals are silicates.
All silicates are made of Oxygen & Silicon joined with other elements.
The silica tetrahedron is the main component of all silicate minerals.
By sharing oxygen atoms, one tetrahedron can join to another to form chains & sheets.

11. II. OTHER MINERAL GROUPS
Carbonates – composed of a metal along with the carbonate compound, CO3
Oxides – are minerals of a metal and oxygen.
Other groups include sulfides, sulfates, and halides.

12. IDENTIFYING MINERALS I. Physical Properties
Streak - the color of the mineral’s powder.
A mineral’s streak is more reliable than color.
Luster - the shine of a mineral.
Metallic vs. Non-metallic luster.
Hardness - the ability to cause or resist a scratch.
Scratches glass or not.
Cleavage - splits easily in one or more direction leaving smooth, flat surfaces.
Fracture – breaks difficultly & unevenly.

13. Streak

14. Luster
Metallic
Non-metallic

15. Cleavage

16. MOHS’ HARDNESS SCALE From softest to hardest
1 - Talc
2 - Gypsum
3 - Calcite
4 - Fluorite
5 - Apatite
6 - Feldspar
7 - Quartz
8 - Topaz
9 - Corundum
10 - Diamond

17. FIELD TEST FOR HARDNESS

18. USES OF MINERALS