1. Minerals

2. What is a Mineral?
Naturally-formed solid substance with a crystal structure
Pyromorphite

3. What do all minerals have in common?
Are formed by natural processes.
Are NOT alive and NEVER were alive
Have a definite volume and shape
Are elements or compounds with a unique chemical makeup
Are made up of particles that are arranged in a pattern that is repeated over and over called a CRYSTAL.

4. Watch “Crystals” by Brainpop…
.What element are diamonds made from?
. What do all crystals have in common?

5. Groups of Minerals
Minerals are grouped by the elements they are made of.
Beryl (Emerald)
Calcite
Amethyst

6. How do minerals form?
1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle))
Fast Cooling = No Crystals (mineraloids)
Medium Cooling = small crystals
Slow Cooling = large crystals

7. How do minerals form?
2) Elements dissolved in liquids (usually water)

8. Mineral Identification
There are six different test that are used to identify what type of mineral a mineral is.
Color
Luster
Streak
Hardness
Cleavage/Fracture
Special Properties

9. Physical Properties of Minerals (can be used to identify the mineral)
Color
Can be misleading
Can vary with the type of impurities

10. Physical Properties of Minerals (can be used to identify the mineral)
Luster
Surface light reflection
metallic = shiny like metal
non-metallic = dull, non-shiny surface
Pyrite has a metallic luster
Calcite has a non-metallic luster

11. Physical Properties of Minerals (can be used to identify the mineral)
Streak
The color of the powdered form of the mineral
The color of the streak can be different than the mineral
Minerals must be softer than the streak plate

12. Streak…can help identify quartz
BUT...

13. Physical Properties of Minerals (can be used to identify the mineral)
Hardness
How easily a mineral scratches materials
Mohs Hardness Scale
Scale from 1 (softest) to 10 (hardest)
Test by seeing if the mineral can scratch different objects like human fingernail, copper, penny, glass, steel file.

14. Find out more… “Electronic” Hardness Test

15. Physical Properties of Minerals (can be used to identify the mineral)
Cleavage & Fracture
The way the mineral breaks
Cleavage—minerals break along smooth, flat surfaces and every fragment has the same general shape
Fracture—minerals that break at random with rough or jagged edges

17. Cleavage or Fracture? 1. 4. 3. 2.

18. Physical Properties of Minerals
Density: how much matter is in a given amount of space.
see if the object floats or sinks in water.
Water’s density is 1:
If it floats = density is less than 1
If it sinks= density is more than 1
*THIS IS CALLED SPECIFIC GRAVITY

19. Physical Properties of Minerals (can be used to identify the mineral)
Other Properties
Specific gravity (*excellent clue to mineral’s identity)
Attraction to magnets
Bending of light
Reaction with hydrochloric acid
Smell & taste

20. Watch Brainpop—“Mineral Identification”
. If a mineral can scratch your fingernail, the mineral is _______________ than your fingernail.
2. What is luster?

21. Quick Hardness Test Penny, pencil, fingernail
1. Use your fingernail to try to scratch the graphite tip of your pencil
2. Now try to scratch the penny with your fingernail
3. Rank these 3 materials in order from softest to hardest on an index card. Explain why you ranked them this way.

22. Watch Classifying Minerals Clip