1. Chapter 3 Minerals
Updated November 2011

2. What is a Mineral?
Mineral- a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition

3. Mineral – Naturally Occurring
Must occur in the natural world
Which of the following is naturally occurring?
Plastic
Brick
Glass
Quartz

4. Mineral - Inorganic
The mineral cannot form from materials that were once part of a living thing. (Living things are said to be organic)
Is coal a mineral?
How does coal form?

5. How Coal Formed

6. Mineral – Crystal Structure
Crystal structure - the repeating pattern of a mineral’s particles forms a solid.
A crystal has flat sides (faces) that meet at sharp edges and corners.

7. Question # 7on the study guide This will not be on the test
What does it mean when a mineral always contains certain elements in definite proportions??
It means that the mineral has a definite chemical composition.
What?? Next slide:

8. Are almost all minerals compounds??
Yes! This means that they are made up of more than one chemical.
Some are pure though:
Question # 9: Name three pure crystalline elements:
Gold
Silver
Copper

9. Mineral Identification
There are 8 properties used to identify minerals. They are:
Color
Streak
Luster
Density
Hardness
Crystal Systems
Cleavage and Fracture
Special Properties

10. Mineral ID…
Color – look at the mineral!!

11. Mineral ID…
Streak – the streak is the color of its powder. To obtain this, rub the mineral against an unglazed porcelain tile.
(The color of the streak is sometimes different than the mineral)

12. Mineral ID…
Luster – describes how light is reflected from a mineral’s surface

13. There are 6 lusters of minerals
Metallic
Glassy (waxy, greasy, pearly)
Submetallic
Dull
Silky
Earthy

14. Mineral ID… Hardness – use Moh’s Hardness Scale
Page 71 in the textbook
Find hardness through a scratch test

15. Moh’s hardness scale cont.…
Hardness can be determined by a scratch test.
A mineral can scratch any mineral softer than itself. (But not any mineral harder)
Example: To determine the hardness of azurite, you could try to scratch it with talc, gypsum, or calcite. But you discover none of them scratch it. Apatite, rated 5 on the scale does, therefore azurite’s hardness is about 4.

16. Mineral ID…
Crystal Systems – 6 systems found on page 73 of the textbook
They are:
Cubic
Hexagonal
Ortrhorhombic
Monoclinic
Tetragonal
Triclinic

18. Mineral ID… Cleavage and Fracture is the way a mineral breaks apart.
Cleavage = a mineral that splits easily along flat surfaces

19. Fracture - how a mineral looks when it breaks apart in an irregular way

20. Mineral ID… Special Properties Fluorescence- Glows in UV light
Magnetism- Attracts ferromagnetic materials
Acid Test- reacts chemically
Optical Properties- bends light
Radioactivity- produces its own energy
Electrical properties- conducts electricity