CH. 2 - MINERALS

MINERALS

Basic building block of rocks

>4,000 minerals identified

Mineral Definition (requirements):

1) Solid

2) Naturally Occurring

Mineral Definition

3) Inorganic – no biologic origin

4) Definite Chemical Composition

Ex: Halite =

Quartz =

Diamond =

Graphite =

Mineral Definition

5) Ordered Crystalline Structure

Ex: Halite (NaCl)

Ordered Crystalline Structure

Diamond = high pressure

- complex bonding of carbon

atoms

Graphite = low pressure

- carbon atoms bond in sheets

Mineral Definition

1. Solid

2. Naturally Occurring

3. Inorganic

4. Definite Chemical Composition

5. Ordered Crystalline Structure

Structure of Minerals

1) Atom – smallest building block

of an element

Composed of atomic particles

- protons (+), neutrons, and

electrons (-)

Periodic Table of the Elements (p. 32)

Balanced Atoms

Atomic Number = number of protons

- defines which element atom belongs to

Atomic Mass = sum of protons & neutrons

Balanced Atoms

Number of electrons = number of

protons

Rule:

1st energy level = 2 electrons max

All other energy levels = 8

electrons max

Balanced Atoms

Valence electrons = electrons in

outermost energy level

Atoms bond b/c they want full

outer shell of electrons

Types of Bonding

1) Ionic Bonding

Ion = atom with an electrical

charge (+) or (-)

- caused by losing or gaining

electrons

Ionic Bonding

Atoms bond b/c opposites attract

(like magnets)

Ex: Halite (NaCl)

Types of Bonding

2) Covalent Bonding

- outer energy levels overlap

- atoms share valence electrons

Ex: Oxygen (O2)

Structure of Minerals

2) Element – composed entirely of

same kind of atoms

- all atoms have same number of

___________

92 naturally occurring elements

Element

Some minerals are elements:

Ex:

Structure of Minerals

3) Compound – combination of

two or more elements

- characteristics are different than

individual elements

Ex: Halite NaCl

Compound

Most minerals are compounds:

Quartz =

Galena =

Hematite =

Chemical Composition of Crust

98.3% of crust composed of 8 elements (Figure 2.15)

Other 84 elements share 1.7% of remaining crust

- includes gold, zinc, lead, carbon, sulfur, silver, …

Mineral Groups

1) Silicate Group - 90% of all

minerals

Basic building block is the silica

tetrahedron SiO44-

Silica tetrahedron (SiO44-)

Negative charge bonds with

positive ions

Other abundant elements of crust

are positive ions (Ex: Mg)

Mineral Groups

2) Nonsilicate Group

Includes:

a) rock-forming minerals

Ex: calcite CaCO3

Nonsilicate Group

b) native elements

Ex: sulfur, copper, gold

c) Metal ores

Ex: galena (PbS)

magnetite (Fe3O4)

Rocks

Aggregate of minerals (mixture)

Some rx are impure quantities of

the same mineral

Ex: Limestone = calcite

(rock) (mineral)

Rocks

Most rx are composed of several

minerals

Ex: Granite = quartz, feldspar,

(rock) hornblende

3 groups of rocks

1)

2)

3)