Earth Science, 6e

Edward J. Tarbuck & Frederick K. Lutgens

Minerals, What for?

Do we need Minerals?

Name a few things made of minerals:

Example: Glass is made from…

Minerals: the building blocks of rocks

Definition of a mineral • Natural• Inorganic• Solid• Possess an orderly internal structure of atoms • Have a definite chemical composition

Mineraloid - lacks an orderly internal structure

Minerals

Physical properties of minerals • Crystal form• Luster• Color• Streak• Hardness versus Tenacity• Cleavage (breaks evenly)

The mineral quartz often exhibits good crystal form

Pyrite (fool’s gold) displays metallic luster

Color, not reliable…

Three examples of perfect cleavage – fluorite, halite,

and calcite

Conchoidal fracture

Minerals

Physical properties of minerals • Fracture (breaks unevenly)• Specific gravity (mineral heftiness)• Other properties

• Taste

• Smell

Minerals

Physical properties of minerals • Other properties

• Feel

• Magnetism

• Double Refraction

• Reaction to hydrochloric acid

Minerals

A few dozen minerals are called the rock-forming minerals (see page 35)

The eight elements that compose most rock-forming minerals are (see page 34)

Minerals

Silicates Minerals (see page 35)

Most common mineral group (90% of minerals)

• Contain the silicon-oxygen tetrahedron • Four oxygen atoms surrounding a much smaller

silicon atom

• Combines with other atoms to form the various silicate structures

The silicate (SiO4)-4 molecule

Common silicate minerals

Potassium feldspar

Minerals

Nonsilicate Minerals ( see page 36)• Major groups

• Oxides

• Sulfides

• Sulfates

• Carbonates

• “Native” elements

Native Copper

Some common non-silicate minerals

An underground halite (salt) mine

The Bingham copper mine in Utah

End of Chapter 1

PRS Test on Minerals

Please do not talk to your neighbor during the test.

Thank you.

1- This silicate (SiO4)-4 molecule hasa: 1 silicon 4 oxygen; or b:1 oxygen 4

silicon

2 - Does this quartz mineral show a: Cleavage faces or b: Crystal form?

3 - What is the luster displayed by this mineral ?

a: metallic; b: non metallic

4 - Do these minerals have a: perfect cleavage; b: absence of cleavage

5 - Does this mineral showa: good cleavage or b: conchoidal fracture?

6 - What mineral is this?a: Calcite or b: Potassium Feldspar

7 - What are the two minerals your fingernail can scratch?

a. Calcite and Gypsum

b. Gypsum and Talc

c. Talc and Calcite

8 - The most reliable way to identify a carbonate mineral is by

a. Luster

b. Hardness

c. Streak

d. Reaction to Hydrochloric Acid

e. None of these

9 - One of these minerals is a Sulfide

a. Calcite (CaCO3)

b. Quartz (SiO2)

c. Gypsum (CaSO4.H2O)

d. Pyrite (FeS2)

e. None of the above

10 - Which term does not define a mineral?

a. Natural

b. Solid

c. Organic

d. Definite crystalline structure

e. Definite Chemical Composition

11 - Which mineral has double refraction, hardness =3, and

reacts with hydrochloric acid?

a. Pyrite

b. Galena

c. Quartz

d. Calcite

e. None of these

THE END

THAT’S ALL FOLKS!

THANK YOU!!!