Regents Earth Science

Regents Earth Science

Unit 2 Rocks & Minerals

Na

me

:

www. BarnesWeb.org

2014-15 edition

Vocab Mineral ID Mineral who am I Mineral Reading Rewview

2


You should know/be able to: Explain how minerals are formed.

Identify a mineral sample by testing the samples physical properties and using the ESRT.

Explain why each mineral has its own unique physical properties.

Explain and identify the silica tetrahedron.

Identify a rock sample as either Igneous, Metamorphic or sedimentary and give a reason

for your identification.

Correctly utilize the Igneous, Sedimentary and Metamorphic rock tables in the ESRT.

Explain how Sedimentary rocks are formed (deposition, cementation, compaction, precipitation,

evaporation)

Describe the identifying features of Sedimentary (fossils, clasts, layers) Rocks and explain how

those features were formed.

Explain how Igneous rocks are formed (also magma vs. lava)

Determine the rate of cooling using crystal size

Explain the differences in formation and characteristics of Extrusive and intrusive igneous rocks

Explain the classifying features of igneous rocks (texture, color, density, crystal size)

Explain how Metamorphic rocks are formed (include contact vs. regional)

Identify the parent rocks of a metamorphic rock (using the ESRT)

Explain Crystals vs. clasts

Explain Bedding (layers) vs. foliation

Describe the identifying features (foliation and banding, identifier minerals) of Metamorphic

Rocks and explain how those features were formed.

Explain the rock cycle, and give examples of how rocks are recycled through the rock cycle.

Efficiently use the ESRT rock cycle diagram

3

Unit 2 Rocks, Minerals & Earth Resources

4


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

5


St

ud

ent

Lear

nin

g O

bje

ctiv

e

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

6


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

7


St

ud

ent

Lear

nin

g O

bje

ctiv

e

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

8


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

9


St

ud

ent

Lear

nin

g O

bje

ctiv

e

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

10


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

11


St

ud

ent

Lear

nin

g O

bje

ctiv

e

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

12


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

13


St

ud

ent

Lear

nin

g O

bje

ctiv

e

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

14


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

15


St

ud

ent

Lear

nin

g O

bje

ctiv

e

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

16


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

17


St

ud

ent

Lear

nin

g O

bje

ctiv

e

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

18


Stu

den

t Le

arn

ing

Ob

ject

ive

Date

Do

No

w

Today’s

Le

sso

n

was….

Clo

sure

Evaluation

SLO

Do Now

Lesson

Participation

Closure

Score

19


Minerals & Rocks

I. Minerals are –

1. __________________________ occurring.

2. Inorganic- No organic matter; ___________________________________________________________ or the remains of living things.

3. Solid - ______________________________________________________________ definite _______________

4. Definite____________________________________________________________________

5. Definite ___________________________________________________________________

a) Examples:

(1) Graphite - ________________________________________

(2) Sulfur - __________________________________________

(3) Talc - ____________________________________________

A. Chemical Composition:

1. Minerals are classified into 2 major classes.

a) __________________________________________– minerals that have silicon and oxygen

groupings; __________________.

(1) combined __________________ one or more __________________________.

Talc - Mg3Si4O10(OH)2

20


(2) Largest group of minerals

(a) ______________________ the earth's __________________.

b) ____________-Silicate – minerals that ________________________________________________

(1) ____________________________________ into several other classes

(a) native ________________________________ - gold, sulfur, silver

(b) __________________________________ - galena, pyrite

(c) __________________________________ - gypsum

(d) __________________________________ - hematite, magnetite

(e) __________________________________ - halite, fluorite

(f) _________________________________- calcite, dolomite

(2) Extremely rare; 8% of the Earth's crust

(3) Few are relatively common, such as calcite.

B. Crystal Structure:

1. A minerals _______________________________________________________________________________

2. Atoms and molecules are arranged in ____________________________________________

geometric ________________________.

3. _________ basic crystal systems/patterns

a) ______________________/ isometric: Galena, Halite, Pyrite

b) _______________________________: Chalcopyrite

c) _______________________________: Quartz, Calcite

d) _________________________________: Olivine, Topaz

21


e) __________________________________: Mica, Gypsum

f) __________________________________: Feldspar, Turquoise

4. Minerals form when…

a) Lava or __________________ cools to ___________________________________________

b) Water ______________________________ and leaves minerals behind.

c) _______________________ becomes supersaturated with mineral particles;

______________________________ will ______________________________ out of the water and

________________________________ as a precipitate.

C. Identifying Minerals: pg _______ of ESRT

1. Minerals can be ________________________________________ their physical and chemical

________________________________________________.

a) Physical Properties: Color ____________________

___________________ Cleavage

___________________ Density

b) Chemical Properties: ______________________________________________________ mineral

_________________________________________________________________________________

2. Color: Not a reliable property; some minerals ________________________________________

______________________________________________________________.

a) Color may _____________________ due to

(1) Natural _________________________________________________

(2) Weathering; ____________________________________________________________

22


b) Malachite - _________________________________________

c) Quartz – ________________________________________________________________

d) Sulfur - ____________________________________________

e) Hematite – _________________________________________________________

3. Streak: The color of a mineral in its _______________________________________.

a) Determined by using a ______________________________________

(1) Quartz - _____________________

(2) Hematite - ____________________

4. Luster: The way a mineral _______________________________________________________________

a) Metallic – Reflects light like a _____________________________________________

(1) _________________________________________________

b) Nonmetallic – Reflects light in more subtle ways

(1) Pearly - ___________________________

(2) _______________________ - Quartz

(3) Dull/____________________ - Bauxite

(4) ____________________ - Talc, gypsum

(5) Brilliant - _________________________

23


5. Hardness: A measure of ________________________________________________________________

a) Determined by a minerals ______________________________________________________;

strength of the bonds and crystal shape.

b) When a mineral is scratched by a substance, that mineral is said to be

______________________________ than the substance.

c) When a mineral scratches a substance, that mineral is said to be

_______________________ than the substance.

d) Moh’s Hardness Scale –

6. Cleavage: When a mineral splits/_______________________________________________

___________________________________________________________________

(a) Mica – one direction; in a _________________________.

(b) Galena – Three directions; in a _________________ shape

a) Determined by atomic _________________________________ of minerals.

(1) ___________________________ is the way a mineral breaks.

(2) __________________________________________ is formed as the crystal grows.

Hardness Name of Mineral

1 Talc

2 Gypsum

3 Calcite

4 Fluorite

5 Apatite

6 Feldspar

7 Quartz

8 Topaz

9 Corundum

10 Diamond

Common Objects

2.5_______________________ 3.5 Copper 4.5 _____________________ _________ Glass 6.5 Steel File _____ _____________________

___________is softer than___________

__________ is harder than ___________

Cleavage

24


7. Fracture: When a mineral breaks __________________________ into curved or

_________________________________

a) Examples: ____________________, bauxite, hematite, __________________

8. Density or ________________ - Minerals have different ________________________, and

vary in weight given the same sample ________________.

9. Chemical Properties:

a) Effervescence:

(1) Calcite- reacts with _____________; producing ________________________

b) ________________________________:

(1) Reaction between Iron (Fe) and the _________________________ in the air

(a) Example: __________________________________

(2) Reaction between copper and air; causes a ________________________

discoloration.

(a) Example: _________________________________

10. Special Properties:

a) Lodestone- Magnetite: naturally _____________________

b) Iceland Spar- Calcite: produces double _________________________

c) Pitchblend - ________________________________

Fracture

25


D. Uses of Minerals:

1. Ore – A mineral that contains _________________ and __________________________, that

can be ______________________ and removed in _________________________ amounts; for a

profit.

a) Metals – elements with ______________________surfaces, are able to conduct

________________ and __________________________________, and are ________________________.

(1) ________________________ - Hematite/Magnetite

(2) _________________________________ - Bauxite

(3) ____________________________ - Chalcopyrite/Malachite

(4) _________________ - Gold

b) Nonmetals – Elements that have ______________ surfaces and are _______________

conductors of heat and _________________________________ and are _________________.

(1) Halite - __________________

(2) Gypsum - _________________

(3) Calcite - __________________

(4) Kaolinite - ________________

2. Alloy - A mixture of two or more_________________________ or a mixture of

26


Common Rock Forming Minerals

12%

12%

39%

11%

5%

5%

5%

3%

8%

Quartz

Potassium Feldspar

Plag-Feldspar

Pyroxene

Amph/Hornblend

Biotite Mica

Clays

Olivine

Other

_____________________________________.

a) Tin + ______________________ = Bronze

b) Copper + Zinc = ______________

c) Iron + Chromium + ______________________________ = _____________________

d) Lead + Tin = __________________________

3. Gems – Minerals that have _________________________________________________; such as

hardness, _________________, luster, _______________________, rarity…

a) Precious Stones: ___________________________________________________

b) Semi-precious Stones: ___________________________________________

c) Gems that are not minerals: _________________________________

E. Minerals and Rocks:

1. Many kinds of ______________________ are ___________________________________________________

a) Ex: __________________________: ______________, feldspar and ____________________.

2. Mono-mineralic – Rocks that are composed of only ________________________________.

a) Ex: _______________________________ is only composed of ____________________.

3. Poly-mineralic – Rocks that are composed of _____________________________ minerals.

4. There are approximately __________________ different ________________________,

27


II. Rocks are - ______________________________ based __________ their method of

_______________________________.

A. There are ________ different rock __________________.

1. _______________________________________

2. _______________________________________

3. _______________________________________

B. Sedimentary Rocks: form in _____________________________________________________________;

from the accumulation of ________________________________________, organic matter or

chemical precipitate.

1. Usually form _________________________________ in lakes, seas or oceans.

2. Mostly composed of quartz, feldspar and _____________________.

Layers of _______________ Pressure/weight Sediment is ______________

___________________and squeezes lower layers. and ______________________

accumulate . into rock.

Silt

Sand

Silt

Clay

Clay

Silt

Pre

ssu

re

Pre

ssu

re

Silt

Sandstone

Shale

Siltstone

Shale

________________

28


3. Types of Sedimentary Textures: pg ______ of ESRT’s

a) _____________________: form from mineral ________________________________ and

_____________________________ that are ____________________________________ and

____________________________________ together. (Lithification)

(1) Compaction: ___________________________by the weight of overlying rock

(2) Cementation: __________________by natural cements in water. (calcite)

After deposition Compaction Cementation

29


b) __________________________/crystalline: form from minerals ________________________

in water, which settle-out or ____________________________

(1) Dissolved ____________________________ are ___________________________________

after water evaporates.

c) _____________________________/bioclastic: form from the accumulation of

______________________________________________________________________ that undergoes a

transformation into rock.

30


(1) Formation of Coal –

4. Sedimentary Rock _______________________________________________________:

a) Composed of __________________, mineral or __________________________________________.

b) Can contain a wide ___________________ of ____________________________________________.

(1) Pebbles, cobbles, boulders, in a sand, silt or clay matrix.

(a) ________________________________________: rounded fragments

(b) ________________________________: angular fragments.

c) Can contain a ______________________________ sediment _________________.

(1) ___________________________: 0.2 cm –0.006 cm; fine to coarse sand. (2) ___________________________: 0.006 cm –0.0004cm; very fine silt. (3) __________________________: less than 0.0004 cm; minute clays

d) Can be organic and may contain ______________________________.

(1) Limestone, sandstone, _____________________________

e) Generally are formed in ____________________________________rock layers; called

_______________________________________________________________.

31


32


C. Igneous Rocks: form from the __________________ and ____________________________________

of molten lava or ________________________________.

1. When molten ______________ or magma cools and solidifies; the ____________________

of different minerals form.

2. The rock contains a crystalline structure of _______________________________ crystals

of different _________________, ______________ and _____________________________.

3. Types of _______________________ rocks: based on the origin of formation

a) ______________________________/Volcanic: form from the ___________________

cooling of ______________________ on or near the Earth’s ________________________.

(1) Rapid cooling _____________________________ allow time for crystals

to ________________________.

(2) Volcanic rocks have __________________ to __________________________________;

giving it a smooth/__________________ texture.

b) _______________________________/Plutonic: form from the _________________ cooling of

____________________ within the Earth.

(1) Slow _________________________ allows time for ________________ crystals to

grow.

(2) Plutonic rocks have _____________________ crystals; giving them a

_______________________/rough texture.

33


Environment of formation

Rate of cooling Grain Size Texture Example

Extrusive

(Volcanic)

Very Fast _______-crystalline

Obsidian

Pumice

Fast Less than 1mm

Basalt

Rhyolite

Intrusive

(Plutonic) Slow 1mm or larger

Granite

Diorite

c) Crystal size Vs. _____________________________________________

(1) _________________________________ in the Earth’s crust _________________________

the cooling ____________________ and crystal __________________.

Rate of Cooling

Very Fast Cooling

Fast Cooling

Slow Cooling

34


4. Igneous Rock Identification: pg _______ of ESRT’s

a) Mafic vs. Felsic

(1) Felsic – ex: ___________________________________

(a) Composition - __________________________________________________

(b) Density - ______________________

(c) Color - ________________________

(2) Mafic – ex: ____________________________________

(a) Composition - ____________________________________________________

(b) Density - ________________________

(c) Color - _________________________

35


(d)

FLESIC

HOW DIFFERENT

HOW ALIKE?

MAFIC

WITH REGARD TO

PATTERNS OF SIGNIFICANCE:

36


D. Metamorphic Rocks: form from ______________________________ rocks; (sedimentary,

igneous, _________________________________) that have been ________________________.

1. Crystals and _________________________________ are rearranged and form new rocks

due to _________________________ with extreme heat (magma) or extreme

________________________________ (orogeny.)

2. Often found in ____________________________________ regions; where deeper

____________________________________ is exposed due to weathering and erosion.

3. Types of Metamorphism:

a) Metamorphic rocks must experience the following conditions in order

to undergo metamorphism:

(1) ____________________

(2) ________________________

(3) ______________________________________________

b) Contact __________________________________________

(1) When rocks undergo metamorphism due to direct _________________

with ________________ or ______________________.

c) ____________________________ Metamorphism

(1) When rocks undergo metamorphism; due to extreme ________________

applied during ____________________________________________________ events.

4. Metamorphism Results :

a) Recrystalization - environments within the crust have ______________________

temperatures and __________________ pressure; cause rocks to ___________________

by recrystallizing the old rock material.

(1) No true melting occurs; it is called a ___________________________________

(2) ____________________________________________________

Contact

Regional

37


(3) Chemical Change/ __________________________________________

(4) _________________________________ / __________________________________

5. Types of Metamorphic Rocks/ ________________________:

a) ______________________________________: Rock has mineral crystals arranged

in __________________________ or parallel _______________________________.

Ex: Mineral Alignment (________________) & Banding(____________________)

(1) Mineral _____________________________________: Minerals join together;

but do_____________ form _____________________________ layers.

(a) Creates a shine or ___________________________ on the rock

(b) ______________________, Phyllite and Schist

(2) Banding: mineral ___________________________ join and ______________________

in __________________________________; Gneiss

(a) An _______________________________ in ________________ and

___________________ usually produces ______________________

bands of alternating ______________________.

(b) Distorted ______________________________: the ______________________

of mineral ______________________ due to extreme

_________________________ exerted on the rock.

38


Metamorphism

b) ___________________________________________/unfoliated: rock ___________________________

have minerals arranged in ________________________________; _______________________

break in layers/sheets.

(1) Ex: _____________________________________________

Texture Metamorphic

Rock

Original Rock Rock Type

Foliated Slate Sedimentary

Schist Metamorphic

Gneiss Igneous

Nonfoliated Marble Sedimentary

Quartzite Sedimentary

Anthracite Coal Bituminous Coal Sedimentary

39


The Rock Cycle: pg _______ of ESRT’s

6. ________________________________________________________________________________________________;

as shown by the diagram below.

Rock Relationships

40


Minerals & Rocks

41


42


Minerals- Who Am I?

1. I have metallic luster and I am used as an ore for sulfur; often known as fool’s gold.

______________.

2. I have the lowest hardness on Moh’s scale, greasy feel, and used as baby powder.

______________.

3. I am colorless to white and I’m used as a food additive usually with pepper.

______________.

4. I’m dark and I break in thin flexible sheets and often used in construction materials.

_______________________

5. I’m black to silver and I am attracted to a magnet. ___________.

6. I’m colorless, I bubble with acid, and often used in cement and lime. __________.

7. I’m also colorless and my powdered form bubbles with acid. ________________.

8. I am a common hard mineral used in ceramics and glass and I contain the element K.

__________________.

9. I’m usually dark red and found in many New York State Metamorphic rocks.

________________.

10. I’m very easily scratched and I’m found in the drywalls of your house.

_________________________.

11. I’m commonly light green and granular and often made into jewelry.

___________________.

12. I am often bright yellow and I’m used in sulfuric acid. __________________.

13. I can have either metallic or nonmetallic luster and used as an ore for iron.

__________________.

14. I’m made entirely of carbon and found in your pencil. __________________.

15. I’m metallic silver, very dense, and an ore of lead. _____________________.

BONUS: I’m made entirely of Carbon and used in drill bits, earrings, and no other mineral

besides myself can scratch me. __________________________________

43


Name Date Literacy Lab - What”s A Mineral? Earth Science

Directions: Take a few minutes to read the article below either online (or on the back of this page.) Write

responses to the statements or questions below. Cut/copy/paste is not allowed – use your own words and

thoughts, based in research if needed. Read more: http://geology.com/minerals/what-is-a-mineral.shtml

Fact-finding: Identify 6 uses of a mineral

Vocabulary: define the three words in the space below.

1. Mineral

2. Commodities

3. Property

Implications: Using information in the article, why are mineral important to life?

44


What are Minerals? by Hobart King

We Use Minerals Many Times Every Day!

Every person uses products made from minerals every day. The salt that we add to our food is the mineral

halite. Antacid tablets are made from the mineral calcite.

It takes many minerals to make something as simple as a wooden pencil. The "lead" is made from graphite

and clay minerals; the brass band is made of copper and zinc, and the paint that colors it contains pigments

and fillers made from a variety of minerals. A cell phone is made using dozens of different minerals that are

sourced from mines throughout the world.

The cars that we drive, the roads that we travel, the buildings that we live in, and the fertilizers used to

produce our food are all made using minerals. In the United States, about three trillion tons of mineral

commodities are consumed each year to support the standard of living of 300 million citizens. That is about

ten tons of mineral materials consumed for every person, every year.

To meet the definition of "mineral" used by most geologists a substance must meet five requirements:

• naturally occurring

• inorganic

• solid

• definite chemical composition

• ordered internal structure

"Naturally occurring" means that people did not make it. Steel is not a mineral because it is an alloy

produced by people.

"Inorganic" means that the substance is not made by an organism. Wood and pearls are made by organisms

and thus are not minerals. "Solid" means that it is not a liquid or a gas at standard temperature and

pressure.

"Definite chemical composition" means that all occurrences of that mineral have a chemical composition

that varies within a specific limited range. For example: the mineral halite (known as "rock salt" when it is

mined) has a chemical composition of NaCl. It is made up of an equal number of atoms of sodium and

chlorine.

"Ordered internal structure" means that the atoms in a mineral are arranged in a systematic and repeating

pattern. The structure of the mineral halite is shown in the illustration at right. Halite is composed of an

equal ratio of sodium and chlorine atoms arranged in a cubic pattern.

Did You Know? Although liquid water is not a mineral, it is a mineral when it freezes. Ice is a naturally

occurring, inorganic solid with a definite chemical composition and an ordered internal structure.

The Word "Mineral"

45


The word "mineral" is used in many different ways. The definition given above is a formal definition

preferred by geologists. The word also has a nutritional meaning. It is used in reference to the many

inorganic chemicals that organisms need to grow, repair tissue, metabolize and carry out other body

processes.

Mineral nutrients for the human body include: iron, calcium, copper, sulfur, phosphorus, magnesium and

many others.

An archaic use of the word "mineral" comes from the Linnaean taxonomy in which all things can be assigned

to the animal, vegetable and mineral kingdoms.

The word "mineral" is also used inconsistently in geology. In mining, anything obtained from the ground and

used by man is considered to be a "mineral commodity" or a "mineral material". These include: crushed

stone, which is a manufactured product made from crushed rocks; lime, which is a manufactured product

made from limestone or marble (both composed of the mineral calcite; coal which is organic; oil and gas

which are organic fluids; rocks such as granite that are mixtures of minerals; and, rocks such as obsidian

which do not have a definite composition and ordered internal structure.

Mineral Commodities in Industry

The construction industry is the largest consumer of mineral commodities. Crushed stone is used for

foundations, road base, concrete, and drainage. Sand and gravel are used in concrete and foundations. Clays

are used to make cement, bricks and tile. Iron ore is used to make reinforcing rods, steel beams, nails and

wire. Gypsum is used to make drywall. Dimension stone is used for facing, curbing, flooring, stair treads, and

other architectural work. These are just a few of the many uses for these commodities in construction.

In agriculture, phosphate rock and potash are used to make fertilizer. Lime is used as an acid neutralizing soil

treatment. Mineral nutrients are added to animal feed.

The chemical industry uses large amounts of salt, lime and soda ash. Large amounts of metals, clay and

mineral fillers/extenders are used in manufacturing.

Physical Properties of Minerals

There are approximately 4000 different minerals and each of those minerals has a unique set of physical

properties. These include: color, streak, hardness, luster, diaphaneity, specific gravity, cleavage, fracture,

magnetism, solubility and many more. These physical properties are useful for identifying minerals.

However, they are much more important in determining the potential industrial uses of the mineral. Let's

consider a few examples.

The mineral talc, when ground into a powder is perfectly suited for use as a foot powder. It is a soft, slippery

powder so it will not cause abrasion. It has the ability to absorb moisture, oils and odor. It adheres to the

skin and produces an astringent effect - yet it washes off easily. No other mineral has a set of physical

properties that are as suitable for this purpose. The mineral halite, when crushed into small grains is

perfectly suited for flavoring food. It has a salty taste that most people find pleasing. It dissolves quickly and

easily, allowing its flavor to spread through the food. It is soft, so if some does not dissolve it will not

46


damage your teeth. No other mineral has physical properties that are better suited for this use. The mineral

gold is perfectly suited for use in jewelry. It can be easily shaped into a custom item of jewelry by a

craftsperson. It has a pleasing yellow color that most people enjoy. It has a bright luster that does not

tarnish. Its high specific gravity gives it a nice "heft" that is preferred by most people over lighter metals.

Other metals can be used to make jewelry but these properties make gold an overwhelming favorite. (Some

people might add that gold's rarity and value are two additional properties that make it desirable for

jewelry. However, rarity is not a property and its value is determined by supply and demand.)

Physical Properties: Determining Factors

The primary characteristics of a mineral that determine its physical properties are its composition and the

strength of the bonds in its ordered internal structure. Here are some examples: Galena, a lead sulfide, has a

much higher specific gravity than bauxite, an aluminum hydroxide.

This difference is because of their composition. Lead is much heavier than aluminum. Diamond and graphite

both consist of pure carbon. Diamond is the hardest natural mineral and graphite is one of the softest. This

difference occurs because of the types of bonds connecting the carbon atoms in their mineral structures.

Each carbon atom in diamond is bonded to four other carbon atoms with strong covalent bonds. Graphite

has a sheet structure in which atoms within

the sheets are bonded to one another with strong covalent bonds but the bonds between the sheets are

weak electrical bonds. When graphite is scratched the weak bonds fail easily, making it a soft mineral.

The gemstones ruby and sapphire are color variations of the mineral corundum. These color differences are

caused by composition. When corundum contains trace amounts of chromium it exhibits the red color of a

ruby. However, when it contains trace amounts of iron or titanium it exhibits the blue color of sapphire. If,

at the time of crystallization, enough titanium is present to form tiny crystals of the mineral rutile a star

sapphire may form. This occurs when tiny crystals of rutile align systematically within the crystalline

structure of the corundum to give it a silky luster that might produce a "star" that aligns with the primary

crystallographic axis.

Specimen of rhodochrosite from the Sunnyside Mine, San Juan County, Colorado. Rhodochrosite is a

manganese carbonate mineral (MnCO3) that is used as an ore of manganese and is also cut as a gemstone.

Most of the things that we use in our daily life are either made from minerals or produced using mineral

products. Antacid tablets are made from calcite, table salt is crushed halite, several minerals are used to

make a wood pencil and dozens of minerals from many different countries are used to make a cell phone.

The mineral "halite" has a chemical composition of NaCl. That means it contains equal numbers of sodium

and chloride atoms. In this case they are electrically charged atoms, known as ions. Those ions are arranged

in a cubic pattern that repeats in all directions. The small sodium ions are positioned between the larger

chloride ions. Most rocks are aggregates of minerals. This rock, a granite pegmatite, is a mixture of mineral

grains. It contains pink orthoclase, milky quartz, black hornblende and black biotite. Did You Know? The

white "m" on a piece of M&M's candy is a titanium oxide pigment, most likely produce from the mineral

rutile.

Review for Unit Two Exam

Chapter 4

Chapter 5

Regents Earth Science

Documents