1. Chapter 5 Atoms, Elements, and Minerals

2. The next few chapters in geology are mostly about rocks
The next few chapters in geology are mostly about rocks. Nearly all rocks are made of minerals, so in order to learn about rocks you need to know something about minerals. In Chapter 5, you will discover that:
Each mineral is made up of specific chemical elements, the atoms of which are organized in a special arrangement.
The chemical makeup and its internal structure determine an element’s physical properties.
3. A mineral can be identified by its physical characteristics, such as: cleavage, crystal form, fracture, hardness, lustre, colour, streak, and specific gravity.

3. What is Matter?
Matter – the substance of which any physical object is composed. Everything is made of matter.
States of Matter:
Solid
Liquid
Gas
Controlling factors:
Temperature
Pressure
Examples: Gold Mercury Oxygen
solid liquid gas

4. The stuff that makes up all matter
The make-up of solid matter on Earth:
Atoms  Elements  Compounds  Minerals  Rocks
(smallest) (largest)
What is an atom?
An atom is the smallest particle of a matter that keeps the properties of that matter. For example, all sodium atoms are essentially identical to all other sodium atoms. Water (H2O) can be broken down into two atoms of hydrogen (H) and one atom of oxygen (O).

5. What are elements?
Elements are the fundamental building blocks of matter. Elements cannot be broken down into smaller units. Elements are pure substances and are made of one or more of the same type of atoms. All elements are listed in the periodic table of the elements.

6. Periodic Table of Elements

7. Element abundances in the crust
All others: 1.5%

8. What are the most abundant elements in the Earth’s crust?
Oxygen (O)
-Oxygen is the most abundant element in the crust (makes up about 50% of the crust)
-Oxygen bonds easily with other elements

9. Silicon (Si)
-Most silicon form bonds with oxygen to form silica
-Quartz (SiO2) is pure silica that has been crystalized
-Any mineral that contains silica is called a silicate

10. Aluminum (Al)
-Aluminum is more common that iron, but difficult to separate from rocks because it binds very tightly with oxygen.
Other elements in the Top 8 include:
Iron Potassium
Calcium Magnesium
Sodium

12. Mineral characteristics
Definition of a Mineral:
naturally occurring
inorganic
solid
characteristic crystalline structure
definite chemical composition
QUIZ!!!
steel plastic sugar table salt mercury ice coal
no, #1
no, #1
no, #1,2
YES!
no, #3
YES!
no, #2
basalt obsidian mica gold paper chalk coral
no, #5
no, #4
YES!
YES!
no, #1,2
no, #2
no, #2

13. Mineral characteristics
Naturally formed
No substance created artificially is a mineral.
examples: plastic, steel, sugar, paper
Inorganic
Anything formed by a living organism and containing organic materials is not a mineral.
examples: wood, plants, shells, coal
Solid
Liquids and gases are not minerals.
examples: water, petroleum, lava, oxygen

14. Mineral characteristics
Characteristic crystalline structure
must have an ordered arrangement of atoms
displays repetitive geometric patterns in 3-D
glass not a mineral (no internal crystalline structure)
Definite chemical composition
must have consistent chemical formula
examples: gold (Au), quartz (SiO2), orthoclase (KAlSi3O8)
basalt (like many other rocks) contains variable ratios of different minerals; thus, has no consistent formula

15. How many minerals are there?
Nearly 4,000 types of minerals
Only ~30 occur commonly (whew!)
Why not more?
Some combinations are chemically impossible
Relative abundances of elements don’t allow more

16. Silicates
Most minerals are silicates (which means they contain silicon & oxygen)
Silicates have a very special structure called a tetrahedron. This tetrahedron is the building block of a the silicate crystals

17. Silicate tetrahedrons can combine together to make much bigger structures.
Diamond is NOT a silicate,
but pure crystallized carbon.
It is a very strong tetrahedron
(and also a mineral).

18. Minerals of the Earth’s Crust
The following are silicate minerals. They are the most common minerals and make up about 90% of the crust.
Feldspars
Quartz
Pyroxenes
Amphiboles
Micas

19. Feldspar
Quartz
Pyroxene
Amphibole
Mica

20. Other common mineral crystals include:
1. Clay minerals (which is another group of silicates)
2. Non-silicates
Example: gypsum
Example: calcite

21. Less common minerals of commercial value:
Halite (salt)
Diamond
Gold
Hematite & magnetite (iron)
Chalcopyrite (copper)

22. Physical Properties of Minerals
Colour
Streak
Lustre
Hardness
External crystal
Cleavage (most important)
Fracture
Specific gravity

23. Class Activity
1.Briefly explain each of the physical properties of minerals. Refer to Properties of Minerals 2. ID some minerals (Resource) Video

24. Quiz Most common element in the crust. Most common mineral.
Which one (or ones) is/are a mineral? Plastic quartz salt
What is geology?
What is the topic of your geology project?