1. Chapter 13
Minerals
Courtesy of Tiffy75 at SlideShare

2. What Is A Mineral?
A mineral is a naturally formed, inorganic solid with a crystalline structure.
Is It A Mineral? It might be, if you can answer yes to the following questions:
Is it a solid?
Is it formed in nature?
Is it nonliving material?
Does it have a crystalline structure?

3. Is It A Solid?
Minerals can’t be gases or liquids!
No Air & No Water

4. Is It Formed In Nature?
Crystalline materials made by people aren’t classified as minerals.
No Man Made Gemstones & No Tires

5. Is It Nonliving Material?
A mineral is inorganic, meaning it isn’t made of living things.
No Teeth & No Bones

6. Does It Have A Crystalline Structure?
Minerals are crystals, which have a repeating inner structure that is often reflected in the shape of the crystal. Minerals generally have the same chemical composition throughout.

7. Does It Have A Crystalline Structure?
Let’s break it down:
Minerals are made up of Elements
Elements are pure substances that can’t be broken down into simpler substances
Atoms are the smallest part of an element
Mineral
Element
Atom

8. Does It Have A Crystalline Structure?
More than one type of atom stuck together is a compound
Most minerals are made up of compounds of different atoms
Sodium +
Chlorine
Halite
z.about.com/d/chemistry/1/0/Y/6/halite.jpg

9. Does It Have A Crystalline Structure?
When atoms are held in a set structure it is called a crystal (or a crystalline structure) 9

10. Two Types of Minerals Minerals that contain Silicon and Oxygen
Silicate
NonSilicate
Minerals that contain Silicon and Oxygen
90% of Earth’s crust is made up of Silicate Minerals
Examples: Feldspar, Biotite Mica & Quartz
Minerals that do not contain Silicon & Oxygen
Examples: Native copper, Gold, Diamond, Calcite, Fluorite and Galena.
mrbarlow.files.wordpress.com/2009/02/diamond.jpg

11. Identifying Minerals
Now that you know your sample is a mineral… we need to learn how to identify what mineral it is
Properties to ID Minerals
Color
Luster
Streak
Cleaving & Fracture
Hardness
Density
Special Properties

12. Identifying Minerals: Color
Not a good indicator for ID
Example: Pyrite (Fool’s Gold) has a golden color normally – but when exposed to weather for a long time it turns black

13. Identifying Minerals: Luster
Luster is the way a surface reflects light
Example: Dull or Shiny
Types of Luster:
Metallic ( Shines like metal)
Submetallic (Metallic but dull)
Nonmetallic (glassy, silky,
Pearly, earthy, waxy)
Add picture from p. 64 13

14. Identifying Minerals: Streak
Streak is the color of a mineral’s powdered form
More reliable than Color because weathering doesn’t change the Streak Color
geology.csupomona.edu/alert/mineral/streak.jpg

15. Identifying Minerals: Cleaving & Fracture
Minerals break in certain ways depending on how the atoms are arranged
Cleaving: When minerals break along flat surfaces
Ex. Diamonds and Rubies
Fracture: When minerals break unevenly or irregularly
Ex. Quartz

16. Identifying Minerals: Hardness
Hardness refers to a mineral’s resistance to being scratched
Example: Diamond is the hardest mineral, Talc is the softest mineral.
Moh’s Hardness Scale:
Scale 1 – 10 (1 softest, 10 hardest)
z.about.com/.../1/0/W/A/1/magnetitemassive.jpg

17. Identifying Minerals: Density
Density is how much matter there is in a given amount of space (Mass/Volume--
unit-grams/cubic centimeter )1mL=1cm3)
Density of Water: 1 g/cm3
Specific Gravity =Object’s Density/Density of Water
The specific gravity of an unknown mineral can tell you its identity

18. Identifying Minerals: Special Properties
Some minerals have unique properties:
Taste (ex. Halite)
Fluorescence (ex. Calcite & Fluorite)
Chemical Reaction (ex. Calcite)
Optical Properties (ex. Calcite)
Radioactivity (ex. Radium & Uranium can be detected in a mineral)
Magnetism (ex. Magnetite & Pyrrhotite)