1. Vocabulary Objectives mineral Luster Cleavage Hardness Gem crystal
Streak
Cleavage
Gem
Ore
Objectives
Define a mineral
Characterize how minerals are identified
What are the different types of metals, non-metals, ores, and gems
Vocabulary
mineral
Luster
Hardness
Streak
Cleavage
Gem
Ore
crystal
Silicates

2. Mineral Characteristics
What is a mineral?
Mineral Characteristics
A mineral is
naturally occurring
formed by natural processes
Inorganic
Never living, never will be
Solid
Specific chemical composition
Definite crystalline structure.
Earth’s crust is composed of about 3000 minerals.

3. Mineral Characteristics
What is a mineral?
Mineral Characteristics
Definite Crystalline Structure
Atoms in minerals are arranged in geometric patterns that are repeated again and again.
A crystal is a solid in which the atoms are arranged in repeating patterns.
Triclinic
Tetragonal
Orthorhombic
Monoclinic
Hexagonal
Cubic

4. Minerals form in 2 ways 1. From Magma
What is a mineral?
Minerals form in 2 ways
1. From Magma
Small crystals form from rapidly cooling magma.
Large crystals form from slowly cooling magma.

5. Minerals form in 2 ways 2. From Solution
What is a mineral?
Minerals form in 2 ways
2. From Solution
If a solution becomes supersaturated, or overfilled, with another substance, mineral crystals may begin to precipitate, or drop out of solution.
When liquid evaporates the element remains and begins crystallize.

6. Mineral Groups About 30 minerals are common in Earth’s crust.
What is a mineral?
Mineral Groups
About 30 minerals are common in Earth’s crust.
Called “rock-forming minerals” because they make up most of the crust.
The vast majority of minerals are made up of the eight most common elements.

7. What is a mineral?
Mineral Groups
Most minerals are formed from the eight most common elements in Earth’s crust.

8. Mineral Groups 1. Silicates
What is a mineral?
Mineral Groups
1. Silicates
Silicates contain silicon, oxygen, and one or more other elements.
make up 96 percent of minerals in Earth’s crust.
Most common: feldspar and quartz

9. Mineral Groups 2. Carbonates
What is a mineral?
Mineral Groups
2. Carbonates
composed of one or more metallic elements with the carbonate compound CO3.
the primary mineral found in rocks such as limestone and marble.

10. Mineral Groups 3. Oxides compounds of oxygen and a metal.
What is a mineral?
Mineral Groups
3. Oxides
compounds of oxygen and a metal.
Hematite (Fe2O3) and magnetite (Fe3O4) are common iron oxides and good sources of iron.

11. Mineral Identification
Identifying Minerals
Mineral Identification
Geologists use several simple tests to identify minerals.
Tests are based upon a mineral’s physical and chemical properties.

12. Six Mineral Identification Tests
Identifying Minerals
Six Mineral Identification Tests
Color is one of the least reliable clues to a mineral’s identity
trace elements or compounds within a mineral can change its color.
2. Luster is the way that a mineral reflects light
is described as either metallic or nonmetallic.
3. Texture describes how a mineral feels.
Texture can be described as smooth, rough, ragged, greasy, soapy, or glassy.

13. Six Mineral Identification Tests
Identifying Minerals
Six Mineral Identification Tests
Streak is the color of the fine powder of a mineral obtained by scratching or rubbing against a hard white surface.
Sometimes, a mineral’s streak does not match the mineral’s external color
5. Hardness is a measure of how easily a mineral can be scratched.
one of the most useful and reliable tests for identifying minerals.

14. Mineral Identification
Identifying Minerals
Mineral Identification
Hardness

15. Six Mineral Identification Tests
6. Cleavage & Fracture - Minerals break along planes where atomic bonding is weak.
Cleavage some minerals split easily and evenly along one or more flat planes.
Fracture is the ability of minerals to break with arclike, rough, or jagged edges.

16. Identifying Minerals
Special Properties
Special properties of minerals also can be used for identification purposes.
A type of calcite called Iceland spar causes light to be bent in two directions, a process known as double refraction, when it passes through the mineral.
Calcite (CaCO3) fizzes when it comes into contact with hydrochloric acid (HCl).
Magnetite, an iron ore, is naturally magnetic.
The mineral sphalerite produces a distinctive rotten-egg odor when it is rubbed vigorously across a streak plate.

17. Identifying Minerals
Mineral Uses
Ores
An ore is a mineral that contains a useful substance that can be mined at a profit.
- If the cost of separating waste material from ore becomes higher than the value of the ore itself, then the mineral is no longer considered to be an ore.
The classification of a mineral as an ore may also change if the supply of or demand for that mineral changes.

18. Identifying Minerals
Gems
Gems are valuable minerals that are prized for their rarity and beauty.
Gems such as rubies, emeralds, and diamonds are cut, polished, and used for jewelry.
In some cases, the presence of trace elements can make one variety of a mineral more colorful and thus more prized than other varieties of the same mineral.