1. Minerals of the Earth’s Crust
Chapter 5
Earth Science

2. What is a Mineral? Basic material of the Earth’s crust
Natural, inorganic, crystalline solid
(organic- made up of living things or the remains of living things.
inorganic- not made up of living things or the remains of living things.)

3. How do you determine a Mineral?
Four basic questions to determine (Need yes to all):
1. Is the substance inorganic?
2. Does the substance occur naturally?
3. Solid or crystalline form?
4. Definite chemical composition?

4. Kinds of Minerals
There are over 3,000 types of minerals. Only 20 of them are common.
Only a few make up 90% of the Earth’s crust: quartz, orthoclase, plagioclase, muscovite, biotite, calcite, dolomite, halite, gypsum, and ferromagnesian (olivines, pyroxenes, and amphiboles.)

5. All minerals are classified into two major groups based on their chemical composition: silicate and nonsilicate.
Silicates make up over 96% of the Earth’s crust.

6. Silicate Minerals
All silicates contain atoms of silicon (Si) and oxygen (O).
For example, quartz, contains silicon and oxygen.
Most silicates contain one or more different kinds of elements.
Feldspars are the most common silicates.

7. Nonsilicate Minerals Make up 4% of the Earth’s crust.
Do not contain silicon.
Six major groups: carbonates, halides, native elements, oxides, sulfates, and sulfides.

8. Crystalline Structure
All minerals have a crystalline structure. A crystal is a natural solid with a definite shape.
Scientists look at the crystalline shape to help determine what type of mineral it is.

9. Part 2: Identifying Minerals
Earth scientists, called mineralogists, conduct tests to determine the types of minerals.
Characteristics of minerals: color, luster (metallic and nonmetallic), streak, cleavage and fracture, hardness (scratch test), crystal shape, and density.

10. Mineral hardness: Mohs Hardness Scale.
-softer minerals are assigned a value of one, for example talc is very soft.
-harder minerals are assigned a value of ten, for example diamond is very hard.
Density = mass divided by volume

11. Special Properties of Minerals
Magnetism
Fluorescence and Phosphorescence
Double Refraction
Radioactivity