Rocks and Minerals Identification

Minerals

A.

What is a mineral?
Mineral Characteristics
shared by all minerals:

■ 1. Natural

– occurs naturally
– NOT man made

What is a mineral?

■ 1. Natural

■ 2. Inorganic

■ 3. Crystalline

– Atoms are

arranged in an
orderly pattern

Multiple Choice

Minerals are....

• Natural, inorganic, crystals

• unnatural, organic, amorphous

• natural, organic, crystals

• natural, organic, amorphous

Multiple Choice

Minerals are inorganic which means

• they are alive

• they taste great

• the are really hard

• they are not living

What is a mineral?

■ 1. Natural

■ 2. Inorganic

■ 3. Crystalline

■ 4. Definite chemical

composition
– Chemical formula
– SiO2 is Quartz

What is a mineral?

■ 1. Natural

■ 2. Inorganic

■ 3. Crystalline

■ 4. Definite chemical composition

■ 5. Solid

– Not a gas, not a liquid

How will we remember this?

■ Natural

■ Inorganic

■ Crystalline

■ Definite chemical composition

■ Solid

Mineral Characteristics shared
by all minerals:

Now ICan Define mineralS!

■ Natural

■ Inorganic

■ Crystalline

■ Definite chemical composition

■ Solid

Multiple Select

All minerals have which of the following characteristics? Choose all that apply.

• Definite chemical composition

• Inorganic

• Solid

• Amorphous

Multiple Choice

Which process produces features that distinguish dioptase from azurite?

• crystallization

• foliation

• lithification

• sedimentation

B. Physical Properties of Minerals

■ 1. Color

– First impression
– Not very reliable because lots of minerals

can occur in many different colors

Quartz

■ Purple Amethyst

Fluorite

•Clear
•Blue
•Green
•Purple

Physical Properties of Minerals

■ 1. Color

■ 2. Streak

– The TRUE color of a mineral
– Color of a mineral’s powder

Streak

Minerals with a hardness greater than “7” usually
don’t create a streak on the streak plate because
they are harder than the Porcelain tile (unless the
streak plate is specially made).

Physical Properties of Minerals

■ 1. Color

■ 2. Streak

■ 3. Hardness

– A mineral’s resistance to being scratched
– Mohs Hardness Scale from 1-10

Hardness depends on how “tightly

packed” the atoms are

Mohs Hardness Scale

1
Talc

2
Gypsum

3
Calcite

4
Fluorite

5
Apatite

6
Potassium feldspar

7
Quartz

8
Topaz

9
Corundum

10
Diamond
Hardest

Softest

Physical Properties of Minerals

■ 1. Color

■ 2. Streak

■ 3. Hardness

■ 4. Cleavage

– Splits along

definite planes

“Cleav” = to split

Cleaver

Physical Properties of Minerals

■ 1. Color

■ 2. Streak

■ 3. Hardness

■ 4. Cleavage

■ 5. Fracture

– Breaks irregularly,

jagged edges

Fracture

Physical Properties of Minerals

■ 1. Color

■ 2. Streak

■ 3. Hardness

■ 4. Cleavage

■ 5. Fracture

■ 6. Luster

– How light shines off a mineral
– Metallic or Nonmetallic

Luster

■ Metallic
■ Nonmetallic

Physical Properties of Minerals:
Used for Identification (I.D.)

■ Color

■ Streak

■ Hardness

■ Cleavage

■ Fracture

■ Luster

What is a mineral?

■ 1. Natural

■ 2. Inorganic

– Is not alive
– Was never alive

Multiple Choice

Which mineral property is the least reliable in mineral identification?

• luster

• streak

• hardness

• color

Multiple Choice

Streak is the color of a mineral's

• luster

• powder

• cleavage

• fracture

Multiple Choice

Which characteristic is measured using the Mohs scale?

• luster

• color

• hardness

• streak

Multiple Choice

The property of a mineral that allows it to break smoothly along internal planes when struck with a hammer

• cleavage

• fracture

• luster

• hardness

C. Special Properties

■ 1. Magnetism

– Attracted to a

magnet

– Contains IRON,

cobalt, or nickel

Special Properties

■ 1. Magnetism

■ 2. Double refraction

– Looking through it, you see “double”
– Ex. Calcite

Special Properties

■ 1. Magnetism

■ 2. Double refraction

■ 3. Fluorescence

– Glows under ultraviolet (UV) light

Fluorescence
under ultraviolet,
UV light

Special Properties

■ 1. Magnetism

■ 2. Double refraction

■ 3. Fluorescence

■ 4. Phosphorescence

– Continues to glow even after the

UV light has been removed

Special Properties

■ 1. Magnetism

■ 2. Double refraction

■ 3. Fluorescence

■ 4. Phosphorescence

■ 5. Piezoelectric

– Electricity is generated from Pressure
– Example: Quartz

Piezoelectric (Pressure=Electricity)

Special Properties

■ Magnetism

■ Double refraction

■ Fluorescence

■ Phosphorescence

■ Piezoelectric

Multiple Choice

The special property that allows some minerals glow under UV light

• magnetism

• double refraction

• phosphorescence

• fluorescence

Multiple Choice

Which property allows a mineral held in ones hand to attract nearby ore?

• double refraction

• phosphorescence

• magnetism

• piezoelectric

D. Identification Tests

■ 1. Hardness

■ 2. Streak (True Color)

■ 3. Acid Test

– Use hydrochloric acid

– Tests for carbonate (calcite)

Caves can form in rocks with
calcite, like here in Harrisonburg!

Acid in
groundwater
dissolves the
calcite

Rock Cycle
A model that
describes the
formation,
breakdown,
and
reformation of
a rock.

Rock Cycle

Magma

Sediments

Igneous

Rock

Metamorphic

Rock

Sedimentary

Rock

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Sedimentary Rock
•Formed when sediments
accumulate and compact
and cement together.
•Often deposited in layers
and contain sand,
pebbles, and frequently
fossils.
•Ex. sandstone, limestone

Rock Cycle

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Rock Cycle

Physical properties of Sedimentary Rocks

• Sand, pebble, and even boulder size particles

• Some may contain fossils

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By what process are
sedimentary rocks broken
down?
Weathering

•By weather (rain, ice,
wind), chemical changes,
and living things (plant).

•Creates lose material
called sediments.

Rock Cycle

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By what process are
sediments moved?
Erosion
•Wind
•Water
•Gravity
•Ice
They are deposited in
layers - Deposition

Rock Cycle

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What are the processes that
form sedimentary rock?
Compaction

Sediments are deeply
buried, placing them
under pressure because
of the weight of
overlying layers.

Rock Cycle

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What are the processes that
form sedimentary rock?
Cementation

•New minerals stick the
sediment together just like
cement.
•This holds the grains
together tightly.

Rock Cycle

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Multiple Choice

The process of making sedimentary rocks that could involve weather, animals, chemicals, and/or wind

• erosion

• deposition

• weathering

• compaction

Multiple Choice

The process of making sedimentary rocks that involves moving sediment from one place to another.

• weathering

• erosion

• compaction

• deposition

Multiple Choice

The process of making sedimentary rocks that involves sticking all the sediment containing; rock, organic matter, fossils, and sometimes glass

• deposition

• weathering

• cementation

• erosion

Sedimentary
Processes

On the next slide type the correct answer for which process occurs at A and B.

Sediments

Igneous

Rock

Magma

Metamorphic

Rock

Sedimentary

Rock
A.

A.

A.

B.

Quick Action – Rock Cycle

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Open Ended

Which process occurs at A and B in the previous diagram?

Rock Cycle

Metamorphic Rock

•Formed by heat and
pressure while buried deep
below Earth’s surface.
•Have a layered or banded
(ribbon like) appearance or
may have crystals.
•Ex. Gneiss, Marble, Slate

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Rock Cycle

Physical Properties of Metamorphic Rocks

• Layers look like ribbons

• Crystals

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Rock Cycle

What are the processes that
form metamorphic rock?
Heat(caused by magma)

•Temperatures high enough to
change its structure but not
to melt it.
•Heat can change
sedimentary, igneous, or
another older metamorphic
rock.

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Rock Cycle

What are the processes that
form metamorphic rock?
Pressure - Caused by intense
collisions and friction of tectonic
plates and pressure from overlying
rock layers.

• Deep under the Earth’s

surface.

• Pressure can change

sedimentary, igneous or
another older
metamorphic rock.

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Metamorphic
Processes

On the next slide type the correct

Sediments

Igneous

Rock

Magma

Metamorphic

Rock

Sedimentary

Rock
A.

A.

A.

B.

C.

C.

Quick Action – Rock Cycle

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Open Ended

What process occurs at C on the diagram on the previous slide?

Rock Cycle

Igneous Rock
•Formed when lava or
magma harden.
•Found near volcanoes
or fissures
•Ex. Basalt, Obsidian,
Granite

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Rock Cycle

Physical Properties of Igneous rock

Fast Cooling

Slow Cooling

Glassy

Large crystals

Holes where gas was trapped

Many colors

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Rock Cycle

What are the processes
that form Igneous rock?
Melting

• Caused by increase in

temperature in rock deep
below the surface of Earth

• Caused by friction

between crustal plates

Lava –molten rock material on Earth’s surface.
Magma – molten rock material under Earth’s
surface.

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Rock Cycle

What are the processes that
form igneous rock?
Cooling and
Hardening
•Melted rock turns solid.
•Slow cooling happens below Earth’s
surface as magma cools forming
large crystals. Ex. granite
•Fast cooling happens on the Earth’s
surface as lava cools forming small
crystals. Ex. obsidian, basalt,
pumice

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Multiple Choice

Which type of rock has wavy ribbon layers?

• sedimentary

• metamorphic

• igneous

Multiple Choice

Which type of rock forms by the process of melting, cooling, and hardening?

• igneous

• sedimentary

• metamorphic

Multiple Choice

Which type of rock forms from extreme heat and pressure?

• igneous

• sedimentary

• metamorphic

Igneous Processes

On the next slide type what which process occur at D and E.

Sediments

Igneous

Rock

Magma

Metamorphic

Rock

Sedimentary

Rock
A.

A.

A.

B.

C.

C.

D.

E.

Quick Action – Rock Cycle

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Open Ended

What processes occurs at D and E on the previous slide?