MineralsFeldspar Quartz

What is a Mineral

A mineral is: The basic materials of Earth’s crust.

• naturally occurring

• is inorganic

• is a crystalline solid

• has consistent chemical composition

How to Determine a Mineral

• Is Fluorite a Mineral?• Does it occur

naturally• Is it Inorganic• Is it a crystalline solid• Does it have a

consistent chemical composition?

IS It a Mineral

• Does it occur naturally

• Is it Inorganic• Is it a crystalline solid• Does it have a

consistent chemical composition?

Sample A is Coal

Sample B is Basalt

Rock Forming Mineral

• Of the 4,000 minerals about 20 minerals can be classified as rock forming minerals. Two of the major minerals forming rocks are Quartz and Feldspar minerals.

Silicate Minerals• Silicate minerals

contain a combination of Silicon and Oxygen

• Feldspar is a common silicate mineral. It is a combination of silicon, oxygen and another element.

• Silicate minerals make up 96% of the Earth’s crust.

Non-silicate Minerals

• Non-silicate minerals do not contain silicon or oxygen and make up 4% of Earth’s crust.

• 6 major groups of non-silicate minerals

• The six groups are carbonates, halides, native elements, oxides, sulfates, sulfides

• Fluorite and Silver are examples

Questions about Minerals

1. What is the definition of a mineral?

2. What are the characteristics of mineral?

3. Is Feldspar a mineral? Why/Why not

4. Is coal a mineral? Why/ Why not

5. About how many minerals are rock forming minerals?

6. What is a Silicate mineral? Give an example.

Questions about Minerals7. What per cent of the Earth’s crust is a silicate

mineral?

8. What are two examples of a silicate mineral?

9. What is a non-silicate mineral? How much of the Earth’s surface is contains non-silicate minerals?

10. What are the 6 six major groups of non-silicate minerals.

11. What are two examples of non-silicate minerals

How to Identify Minerals Properties of Minerals

• Color: Is easy to observe. Some minerals have very distinct color.

• Color is not always the most reliable identifier of minerals

• Streak: The color of the mineral in powder form. Color of the mineral when rubbed on a ceramic tile.

How to Identify Minerals Properties of Minerals

• Luster: The light that is reflected from the mineral’s surface

• Luster can be classified as• metallic Luster: Minerals that reflects light

like a polished metal, Galena• glassy Luster: Minerals that look like

glass, Quartz• waxy Luster: Minerals that have an

appearance of candle wax, Talc

How to Identify Minerals Properties of Minerals

• Pearly Luster: Minerals that look like a pearl, Mica

• Brilliant Luster: A mineral that is bright and sparkles, Diamond

• Dull Luster: A mineral that lacks shiny appearance, Gabbro

Example of Mineral Luster

» • Galena: Metallic Quartz: Glassy

• Talc: Waxy Mica: Pearly

• Diamond: Brilliant Gabbro: Dull

How to Identify Minerals Properties of Minerals

• Cleavage: Minerals split along specific planes of weakness to form smooth, flat surfaces

• Fractures: Minerals break unevenly, into pieces that have curved or irregular surfaces.

How to Identify Minerals Properties of Minerals

• Types of Fractures

• Uneven Fractures: Rough surface

• Splintery Fracture: Looks like a broken piece of wood.

• Conchoidal Fractures: Curved Surface

How to Identify Minerals Properties of Minerals

• Hardness: The ability of a mineral o resist scratching.

• Mohs Hardness Scale: The list of ten minerals in order of hardness with Talc a Mohs hardness of 1 the softest. Apatite a Mohs hardness of 5 is in the middle. Diamonds with a Mohs hardness of 10 the hardest mineral.

How to Identify Minerals Properties of Minerals

• Mohs Scale of Hardness

Question on Mineral Identification

• 1. What are the 5 Physical Properties used for Mineral Identification?

• 2. How is color used to identify minerals? Why is color not a reliable clue to identify minerals?

• 3. What is streak of mineral? How is streak used to identify minerals?

• 4. Why is streak a more reliable clue than is color for identifying minerals?

Question on Mineral Identification

5. How is luster used to identify minerals?

6. What are the 6 classifications of luster used to identify a mineral? Give an example of each one

7. How is Cleavage used in identifying minerals?

8. How is Fracture used in identifying minerals?

Question on Mineral Identification

10. How does hardness help to identify minerals.

11. What is Mohs hardness Scale?

12.How is Mohs hardness scale used to identify minerals?

15. What is the softest mineral or 1, what mineral is in the middle or 5, what mineral is the hardest or 10.