Earth Science, 6e Edward J. Tarbuck & Frederick K. Lutgens

Minerals, What for?  Do we need Minerals?  Name a few things made from minerals: Example: Glass is made from… Steel Pencil lead Bullets Sheet rock

Structure of an Atom

How atoms are constructed  Atomic number or atom’s electrical charge: number of protons of the atom  Atomic mass number or atomic weight: Neutrons plus protons

Atomic Bonding  Atomic Bonds  Ionic Bonds: Electron Transfer  Covalent Bonds: Electrons sharing  Metallic Bonds: Free electrons  Ions: Atoms that gain or lose electrons  Isotopes Same atom with a different weight

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

Conchoidal fracture

Pyrite (fool’s gold) displays metallic luster

Color, not reliable…

Three examples of perfect cleavage – fluorite, halite, and calcite

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 (SiO 4 ) -4 molecule

Common silicate minerals

Potassium feldspar

Minerals  Nonsilicate Minerals ( see page 36) Major groups Oxides Sulfides Sulfates Carbonates Halides “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 (SiO 4 ) -4 molecule has a: 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 show a: 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!!!