Minerals Minerals naturally occurring - PowerPoint Presentation

Slide1

Minerals

Minerals

naturally occurring

excludes synthetic minerals

inorganic

non living processes form them

chemically specific

has a unique proportion of elements

crystalline solid

atoms are arranged in specific 3-D patterns

Definition:

Building blocks of rocks

Part of the Geosphere; found in Hydrosphere (hard water); essential for Biosphere (life needs it!); Atmosphere assists in alteration (weathering); Exosphere provided raw materials (stars create elements).

Slide2

Atoms

Protons - positive charge +1

Neutrons - no charge

Have a mass of 1- unit Have a mass of 1- unit

Electrons- have negative charge (-1) & negligible mass

Slide3

Atomic Mass

& Number

•

>

•

>

>

•

Isotopes

>

•>

•

>

>

Atomic Number

The number of protons in an atom.

Atomic Mass

The number of protons + neutrons +electrons.

How isotopes of an element differ from one

another.

•

Isotopes

>

Atoms of the same element that have

different numbers of neutrons, yet still have

the usual number of protons for that particular

element.

Slide4

Isotopes

Isotopes

Slide5

Periodic Table of Elements

Periodic Table of Elements

•

table 2-2, p. 23

Slide6

Ions

Ions

•

atoms or groups of atoms that have an electrical

charge

-

results from gaining or losing electrons

•

Anion

-

negatively charged atom

-

e.g. Cl, O

2

,

•

Cation

-

positively charged

-

e.g. Na, K, Fe

2

•

Complex

-

a group of atoms with a charge

-

e.g. SO

4

, CO

3

•

atoms or groups of atoms that have an electrical

charge

-

results from gaining or losing electrons

•

Anion*

-

negatively charged atom

-

e.g. Cl, O

2

,

•

Cation*

-

positively charged

-

e.g. Na, K, Fe

2

•

Complex

-

a group of atoms with a charge

-

e.g. SO

4

, CO

3

Slide7

Chemical Bonds- control many physical properties

•

Covalent

-

Atoms

share

their outer-most electrons with another atom

-

Very strong bond

•

Covalent

-

Atoms

share

their outer-most electrons with another atom

-

Very strong bond

•

Ionic

-

Atoms get rid of electrons from their outer-most shell.

-

results in a charged (+ or -) atom

-

not as strong as above

•

Ionic

-

Atoms get rid of electrons from their outer-most shell.

-

results in a charged (+ or -) atom

-

not as strong as above

•

Metallic

-

A sea of electrons surrounding nuclei

-

Electrons freely exchanged among atoms

-

Metals make good conductors!

-

can be strong

•

Metallic

-

A sea of electrons surrounding nuclei

-

Electrons freely exchanged among atoms

-

Metals make good conductors!

-

can be strong

•

Van der Waals

-

electrostatic charge

-

weak bond

•

Van der Waals

-

electrostatic charge

-

weak bond

Slide8

Carbon

Different chemical bond types result in different minerals with different properties, despite being composed of the same element

Slide9

What is a physical property?

Identify a physical property found in minerals.

Slide10

Physical Properties

Physical Properties of Minerals

•

Color

•

Luster

•

Streak

•

Hardness

-

Moh's Relative Scale

•

Crystal Habit

-

The way it grows

•

Cleavage or Fracture

-

breaks into planes (flat surfaces)

•

Density (Specific Gravity)

•

Color

•

Luster

•

Streak

•

Hardness

-

Moh's Relative Scale

•

Crystal Habit

-

The way it grows

•

Cleavage or Fracture

-

breaks into planes (flat surfaces) or not

•

Density (Specific Gravity)

•

Related to the atomic

structure & type of

bonding

Slide11

Color

Easiest to identifyCan be diagnostic (e.g., azurite = bright blue)But commonly misleading due to extreme variability impurities in between crystalline structure

impurities incorporated into the crystalline structureExamples in Quartz

green

blue

yellow (citrine)

pink (Rose)

purple

(Amethyst)

clear

(Rock crystal)

brown

(Smoky)

Slide12

Moh's Relative Hardness Scale

Moh's Relative Hardness Scale

Controls how resistant rocks are to erosion

1

T

alc- (softest)

>

T

exas

2

G

ypsum

>

G

irls (or

G

uys)

3

C

alcite

>

C

an

4

F

luorite

>

F

lirt

5

A

patite

>

A

nd

1

T

alc- (softest)

>

T

exas

2

G

ypsum

>

G

irls (or

G

uys)

3

C

alcite

>

C

an

4

F

luorite

>

F

lirt

5

A

patite

>

A

nd

6

F

eldspar

>

F

or

7

Q

uartz

>

Q

uarters

8

T

opaz

>

T

hey

9

C

orundum

>

C

an

10

D

iamond- (hardest)

>

D

ance

6

F

eldspar

>

F

or

7

Q

uartz

>

Q

uarters

8

T

opaz

>

T

hey

9

C

orundum

>

C

an

10

D

iamond- (hardest)

>

D

ance

3.5 copper penny

2.5 fingernail

5.0 streak plate*

5.5 plate glass*

6.5 steel file /nail*

* These items can be slightly harder or softer depepnding on how they were made, and what is in them

Slide13

Physical properties continued…

Cleavage vs Fracture vs Crystal shape all related to chemical elements and types of bondsCleavage - the tendency to break along a plane typically a zone of weak chemical bonds

Fracture - the tendency to break in non-planar surfaces most notable is conchoidal fracture- curved conical shapes common in quartzCrystal habit- the 3 dimensional shape of minerals as they grow- can be quite spectacular and diagnostic

Slide14

Slide15

Crystal examples

Peridot

Fluorite

Pyrite

Quartz

Slide16

The mineral Quartz, as well as some kinds of rocks, exhibits this unique kind of fracture

Slide17

Other properties

Streak- the color of the powdered mineral against a white backgroundLuster- the outer appearance- e.g. metallic,

and non-metallic such as: vitreous,, resinous, waxy, greasy, pearly, silky, adamantine.Special properties taste, smell, reactivity to acids (HCl), magnetism, pleochroismDensity- the weight per unit volume- a measure of how closely packed the atoms are

Slide18

Why are minerals physical properties important?

Slide19

Common elements in the crust

Silica (Si) - makes silicate minerals with oxygenOxygen (O) - makes silicate, oxide, carbonate, sulfate, minerals when combined with other elementsAluminum (AL) - a “garbage can” element- in many classesIron (Fe) - another “garbage can” element-in many classes

Magnesium (Mg) - another “garbage can” element-in many classesCalcium (Ca) - contributes to silicate species and carbonates Sodium (Na) - contributes to halide and silicates

Slide20

Mineral Classes (1:2)

Mineral Classes

•

-

Quartz, Feldspar, Biotite, Muscovite

•

-

Hematite, Magnetite

•

•

•

Silicates- Silicon-oxide Ion (Si O )

x

-

Quartz (SiO

2

), Feldspar, Biotite, Muscovite

•

Oxides- Oxygen (O )

x

-

Hematite (Fe

2

O

3

), Magnetite (Fe

2

O

4

)

•

Carbonates- Carbonate anion (CO )

3

2-

-

Calcite (CaCO

3

), Dolomite, Malachite

(Cu

2

(CO

3

)(OH)

2

)

•

Sulfates- Sulfate anion (SO )

4

2-

-

Gypsum (CaSO

4

) 2(H

2

O), Anhydrite, Barite

x

- variable number of the element

x

- variable number of the element

x

Native elements- Pure element

-

Gold, Silver, Copper, Sulfer

•

Halides- F, Cl, Br, I

-

Halite, Sylvite, Fluorite

Sulfides- Sulfur (S) anion

-

Galena (PbS), Cuprite (CuS), Sphalerite ((Zn,Fe)S)

•

•

Native elements- Pure element

-

Gold (Au), Silver (Ag), Copper (Cu), Sulfur (S)

•

Halides- contain F, Cl, Br, I anions

-

Halite (NaCl), Sylvite (KCl), Fluorite (CaF

2

)

•

•

•

Slide21

Slide22

Importance as Rock Builders

Importance as Rock Builders

•

All rocks are composed of Minerals.

•

12 or so are considered common.

>

Olivine, Augite, Hornblende, Biotite

-

darker colors- Green, Blue, Black, Brown

>

Quartz,

>

>

Muscovite, Calcite, Dolomite, Gypsum, Halite

-

lighter colors- Pink, White, Yellow, Gray, Clear

•

All rocks are composed of Minerals.

•

12 minerals are considered common.

>

Olivine, Augite, Hornblende, Biotite

-

darker colors- Green, Blue, Black, Brown

>

Quartz,

>

*Orthoclase, *Plagioclase (*feldspars),

>

Muscovite, Calcite, Dolomite, Gypsum, Halite

-

lighter colors- Pink, White, Yellow, Gray, Clear

Slide23

Olivine

Augite

Hornblende

Biotite mica

Fe, Mg-rich Silicates

Slide24

Quartz

Potassium

feldspar

(Orthoclase)

Plagioclase

feldspar

Muscovite

Quartz & Al-rich Silicates

Slide25

Optical Calcite- CaCO

3 shows double refraction.

Carbonates

Dolomite CaMg(CO3)2

rhombohedral crystal

White calcite CaCO3note rhombohedral cleavage in all three carbonate samples shown

Slide26

Halite—NaCl

Sulfides, Sulfates & Halides

Galena—

PbS

forms of Gypsum-

CaSO

4

•2H

2O

Selenite

Alabaster

Satin spar

Slide27

Importance of Minerals

Importance of Minerals

•

>

Na, Salt-NaCl

>

Cl, Salt-NaCl

>

Fe, Hematite -Fe

2

O

3

>

Mg, Dolomite-(Ca,Mg)

2

CO

3

>

Ca, Calcite-CaCO

3

>

K, Sylvite-KCl

•

>

Au-Gold, Ag-Silver, Cu-Copper

>

PbS-Galena (Lead)

>

Fe

2

O

3

-Hematite (Iron)

>

Al

2

O

3

-Corundum (Aluminum)

•

>

Diamond- C, Aquamarine-Be

3

Al

2

(Si

6

O

18

),

>

Ruby, Sapphire-Al

2

O

3

•

Contain elements essential for life.

>

Na, Salt-NaCl

>

Cl, Salt-NaCl

>

Fe, Hematite -Fe

2

O

3

>

Mg, Dolomite-(Ca,Mg)

2

CO

3

>

Ca, Calcite-CaCO

3

>

K, Sylvite-KCl

•

Economically significant

>

Au-Gold, Ag-Silver, Cu-Copper

>

PbS-Galena (Lead)

>

Fe

2

O

3

-Hematite (Iron)

>

Al

2

O

3

-Corundum (Aluminum)

•

Aesthetically pleasing GEMSTONES!

>

Diamond- C, Aquamarine-Be

3

Al

2

(Si

6

O

18

),

>

Ruby, Sapphire-Al

2

O

3

Slide28

Where do rocks come from?

•

Building blocks of all rocks are minerals

•

Some minerals form as molten rock cools

•

Some minerals form as chemical precipitates

•

Some are produced by chemical reactions (weathering)

•

Some are “manufactured” by living things

Biotite mineral grain

Biotite mineral grain

Feldspar

mineral

grain

Feldspar

mineral

grain

Quartz mineral

grain

Quartz mineral

grain