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UNIT II
Rocks, Minerals,
& Resources
Presentation created by Mr. Elliott from Fort Plain Central School. Modified by Mr. Oliver Summer 2012.
Mineral Display at
American Museum of
Natural History in NYC
Start Unit II Objective Page Don’t forget to leave a column for dates.
• #1. What are minerals and describe their
characteristics?
• #2. Describe properties of minerals
including the seven basic physical
properties of minerals.
(ESRT p.16)
Introduction
• Lithosphere
– includes crust and small portion of upper
mantle
– Made of solid materials called rock.
• Building blocks of rock are called minerals.
• Rocks composed of single mineral called
monomineralic.
• Rocks composed of many minerals called
polymineralic.
Polymineralic Rock
Monomineralic Rock
Rock Salt
(made of halite only).
_________________________
_________________________
_________________________
_________________________
_________________________
_________________________
• *Mineral: Naturally formed material made up of one or more elements.
In order for a material to be a mineral it must be (have):
Naturally occurring
Inorganic (not from a living thing)
Crystalline
Solid material with definite shape
Definite Molecular structure
Specific physical properties
There are over 2,400 minerals that have been identified on Earth! Of
these, there are about a dozen of them that are so abundant that they
make up more than 90% of the Lithosphere. These very abundant
minerals are called the “rock formers”.
A. Minerals
•Minerals are made up of elements.
•Element: A substance composed of atoms which can
not be broken down into a more simple substance.
•Some minerals are made up of only one element but
most are made up of two or more elements and are
called compounds.
*Native Element Minerals: Minerals that occur in nature as single elements.
(Ex. Gold, iron, graphite, diamond, sulfur)
Halite (compound)
Diamond (only 1
element carbon)
ESRT p.16
Chart from cover (p.1) of ESRT
Be careful as % by
mass and volume
aren’t the same!
*A Minerals physical properties
are determined by its:
Internal arrangement of atoms!
aka: bonding or atomic structure
Internal structure of Halite
II. Physical and Chemical
Properties
The identification of minerals is done on the basis of well
defined physical and chemical properties
Physical Properties: ________________ Things you can see. Chemical Properties: _____________________________
______________ How a certain substance reacts with
other substances. Also includes: ________________________________ Things associated with atomic structure.
Carbon Atoms
(Graphite and Diamond)
Silica Tetrahedron
Mineral Review
*A. Color:
Unreliable for two reasons:
1. _______________________________
• Ex: ______________
Different minerals are the same color.
and Halite calcite
2. _____________________________ One mineral may have many colors.
Only a small impurity can easily change the mineral color.
• Ex: ______ Calcite or classroom samples of quartz
B. Streak: _______________________________ The color of a mineral in powder form.
• We do a streak test using a __________ (an unglazed
piece of porcelain tile)
Streak plate
Note: The color of a mineral may be very different than
the streak.
Streak is: _______________________ More reliable than the color.
*
*
Streak (not listed for
all minerals)
C. Hardness: __________________________________ Resistance of a mineral to being scratched.
• A hard mineral will make a scratch on a softer mineral
• To compare the hardness of minerals, scientists have
developed a scale called the: __________________ Moh’s scale of hardness.
• This scale also: ________________________________ compares hardness of common objects
*
(Feldspar)
(Iron nail)
(Streak plate)
a) Metallic: _________________________ If a mineral shines like a metal.
• Ex: ________________________ Galena, Magnetite, and Pyrite
b) Nonmetallic: _______________________________ If a mineral does not look like a metal.
• Ex: __________________________________ Glassy, Waxy, Greasy, Earthy, Dull, etc…
• Luster can either be metallic or nonmetallic.
The appearance of light reflected from a mineral’s
surface. D. Luster: _________________________________________
_______
Examples of Nonmetallic Luster
Earthy Glassy
Waxy
Dull
These zones of weakness appear as smooth planes or surfaces.
Cleavage: The tendency of a mineral to break along zones
of weakness or flat sides.
E: Cleavage vs. Fracture
Fracture: breaking unevenly, no definite cleavage.
Beryl (Aquamarine)
Basal Cleavage
(One directional)
Ex: Mica
Rhombic Cleavage
(three directional not
at right angles)
Ex: Calcite
Cubic Cleavage
(three directional
at right angles)
Ex: Halite
Conchoidal Fracture
Ex: Obsidian
Remember: If a mineral breaks
evenly with cleavage or unevenly
with fracture depends on the
internal arrangement of its atoms.
The geometric shape of a mineral due to its
internal arrangement of atoms.
F. Crystal Forms: ________________________________
_______________________________
*
G. Specific Gravity: _____________________________________
___________________
The ratio of the density of a mineral compared
To the density of water
•The Density of pure water is 1g/cc .
•So, if a mineral had a specific gravity of 3, the density of the
mineral would be: ____. 3 g/cc
= 3 g/cc 1 g/cc
Divide density
of mineral by
density of water
3 g/cc 1 g/cc
Units cancel
= 3
Specific gravity
of mineral
What is going on mathematically?
So specific gravity is just like density, but
with no units…
*
Calcite Reacts with Acid: When HCl is placed on a
clean surface, it gives off bubbles of CO2 .
Carbonates react
with dilute HCl and
other acids by
fizzing or bubbling
(releasing CO2 gas)
H) Special Properties of Some Minerals
Magnetite exhibits magnetic properties.
Halite tastes like salt
Talc feels slippery.
Talcum Powder
Fluorescence: Mineral emits visible light when
illuminated with high energy light
(ultraviolet).
Phosphorescence: Mineral emits visible light
even after ultraviolet light is switched
off. (glows in the dark.)
• Crystalline- atoms inside are bonded in a
particular pattern or structure
– Depends on “internal arrangement” of atoms
• Two minerals with the same chemical
composition but different crystal structure
may have very different properties.
a) Minerals are crystalline.
• Examples:
– Graphite and Diamond
• Both made of pure Carbon
• Different Bonding
• Graphite-weak bonds, very soft, used in pencils
• Diamond-strong bonds, very hard, jewelry/sawblades
Diamond
Graphite
• Another Example:
– Sand and Quartz or Glass
• Both composed of SiO2
• Different bonding, very different properties
Quartz
Quartz Sand
b) Minerals may be grouped according to the
elements of which they are made, or the
compounds which they can form.
• Examples:
– Oxides- oxygen with another element
– Carbonates- metal combined with CO3
(carbonate formula)
– Silicates- silicon bonded with oxygen
• Silicate formula- SiO4
• Silicate building block- tetrahedron
Iron oxide (rust)
Calcium carbonate
(limestone)
Cover of ESRT’s The two most abundant elements in Earth’s
crust by mass and volume are?
How many minerals in your ESRT’s contain both?
______________minerals are the most common on Earth! Silicate
Igneous Rock Objectives
• #3. How are igneous rocks formed? (ESRT p.6)
• #4. Describe how igneous rocks can be classified
according to either mineral composition or where
they were formed. (ESRT p.6)
• #5. Explain how igneous rock texture is related to
crystal size. (ESRT p.6)
3 Families of Rocks
• Igneous
• Sedimentary
• Metamorphic
Let’s start first with the mother of all rock families….
Igneous – Latin igneus, from ignis fire
“Of, relating to, or resembling fire.”
Source: Merriam-Webster
1. Igneous Rocks: Form from the solidification and/or
crystallization of liquid or molten rock
____________: The process of becoming a solid igneous rock.
____________: Cooling of magma or lava creates crystals.
Solidification
Crystallization
B1 Igneous Rocks
____________: Molten rock underground. Magma
Lava ____________: Molten rock above ground.
Mineral crystals may form resulting in the igneous rock having a
crystalline texture.
***Crystals within a rock are a good indicator of an igneous origin.
II. Igneous Rock Texture and Crystal Size
The texture of the igneous rocks (size of the crystals) is dependent
upon the rate of cooling.
If molten rock cools slowly the crystals will be LARGE.
_______ crystals mean ______ texture (_________). LARGE coarse Phaneritic
If molten rock cools rapidly the crystals will be small.
Small crystals mean fine texture (Aphanitic).
When molten rock is quenched (cooled extremely fast), no crystals
form and is said to have a glassy texture. Ex: obsidian
Vesicular rocks are created when gases remain trapped in
a quickly cooling rock. Air pockets, called vesicles, are
the visible evidence. Ex: Scoria
Graph showing relative rate of cooling
vs. crystal size of igneous rocks
Rate of Cooling
Slow Fast
Cry
stal
Siz
e
Large
Small
III. Environment of Formation: _____________________.
Intrusive: _______ rocks produce _____________________
crystals due to slow underground cooling from magma
Plutonic
Where the rock solidified
Large (1 mm and larger)
Extrusive: ________ rocks produce ___________________
crystals because lava cools faster near or on Earth’s surface
Volcanic Small (less than 1 mm)
Intrusive igneous rock:
Extrusive igneous rock:
Deep Underground
Near or on Earth’s Surface
IV. Composition: ___________________________________. The type of minerals that make up the rock
Rocks that are:
Mafic : ______________________________
______________.
Dark in color, high in density,
high in iron and magnesium
Felsic : ____________________________
_______________.
Light in color, low in density,
high in Aluminum
Exception: Obsidian is dark color but felsic composition.
Felsic Mafic
C. Density: _________________________________. Depends on the composition of the rock
High density _____ in color and _____ in composition. Dark Mafic
Low density _____ in color and _____ in composition. Light Felsic
Mafic Felsic
3. Classification of Igneous Rocks
Classification based on: A. Color: _______________________.
Exception: ________ Obsidian
The overall color of the rock
Light colored rocks are composed primarily
of: __________________. Quartz and feldspars
Dark colored rocks are composed primarily
of: __________________. Pyroxene and Olivine
Now let’s take a look at your ESRT’s
• V. Igneous rocks of different composition
may form from the same body of magma.
– some minerals, like quartz and mica melt and
solidify at low temperatures and take a long
time to solidify out of hot magma.
– Other minerals such as olivine and pyroxene
melt and solidify at higher temperatures. These
minerals settle out of magma quicker.
This is reason that igneous rocks containing olivine do not
usually contain quartz or mica.
Continental Crust vs. Oceanic Crust
• Composition
• Density
• Color
• Rock Type
Continental Crust Oceanic Crust
felsic mafic
low high
light dark
granite basalt
Sedimentary Rock Objectives
• #6. What is a sedimentary rock and what
are three good indicators of one?
(ESRT p.6)
• #7. Describe the three types of sedimentary
rock and how each is formed.
(ESRT p.7)
B2 Sedimentary Rocks Weathering breaks rock and produces sediments which are
transported by water, wind and glaciers. Sediments can form
sedimentary rocks in a number of ways.
Sedimentary rocks are usually found as a thin coating or
veneer on top of other rocks! (like dust on your window sill.)
Sedimentary rock often contain rounded particles cemented in
layers because running water is the major transporting agent.
Many of the rocks form under large bodies of water in 3 major
ways.
I. Clastic Sedimentary Rocks:
Microscopic
clay-sized
fragments
Formed from sediments by the processes of
compression (compaction) and cementation
Compression-
pressure of ocean
water and above
sediments
compact small
particles into
rock.
Very small compacted clay particles can form shale.
I. Clastic Sedimentary Rocks continued:
Cementation- sediments are
combined with mineral cements
that precipitate out of ground water
Precipitate means settle out of solution
Three common cements are
silica, iron and lime.
Common cemented clastic sedimentary rocks are
sandstone, breccia and conglomerate.
II. Chemical Sedimentary Rocks
(Crystalline, not clastic):
•Form from processes of evaporation and precipitation
•Evaporation- salt water evaporates (turns to gas) and
leaves solid minerals behind to form rock called
evaporites
•Precipitation- Solid minerals settle to bottom of salt
water solution forming rock called precipitates
•Evaporites and precipitates are monomineralic
meaning composed of only one mineral. Four common
evaporites and precipitates are rock salt, rock gypsum,
dolostone and limestone.
III. Biological or Organic
Sedimentary Rocks (Bioclastic)
• Rocks formed from the remains of plant or
animal materials
•Bituminous Coal
comes from
compacted plant
remains
•Fossil limestone
comes from
cemented shells and
animal remains
Sedimentary Rocks can be classified into 3 major groups:
Clastic
(Fragmental)
Bioclastic
(Organic)
Crystalline
(Chemical)
Underwater
(on the seafloor)
In the presence
of water In the presence
of water
Fragments of
broken rocks
Salts
(Monominerallic)
Origin
Composition
Method of
Lithification
(rock formation)
Compaction &
Cementation
Precipitation
and evaporation
from salty water
Compaction
of dead
material
Once-living
remains
Sedimentary Rocks are the official
rock of “Fossils”
***If you see a fossil, it’s in a sedimentary rock!
Presence of sediments
Layers in Rock
Three good indicators of Sedimentary Rocks are:
Presence of Fossils
Metamorphic Rock Objectives
• #8: How are metamorphic rocks formed and
what are some indicators that metamorphism
has taken place? (ESRT p6&7)
• #9. Explain the two types of metamorphism.
• Metamorphism usually takes place deep within the
Earth. This is where the very high temperatures,
high pressures and hot chemical solutions can be
found that cause recrystallization forming
metamorphic rock.
B3 Metamorphic Rocks
Larger
garnet
crystals in
schist grow
due to
intense heat
& pressure!
•Metamorphism results in recrystallization of unmelted
minerals under high temperatures and pressures.
•These extreme conditions cause the mineral crystals to
grow and new minerals to form without melting which
is the process called recrystallization.
The original rock from which metamorphic rocks are formed
is called the __________. Parent Rock
Parents Rock!
Not a
Metamorphic
rock
Parent rock may be igneous, sedimentary or metamorphic.
They look similar
but are different in
the following
ways…
Parent (Shale)
Metamorphic
“Version” (Slate)
Indicators of Metamorphism:
• Metamorphic rocks can be
hard, very dense and less
porous!
• Distorted structure:
Metamorphic rocks also show
bending & twisting due to
uneven pressure. Original
sedimentary rocks layers may
become bent or folded from
pressure as they change into
metamorphic rock.
•Garnet and/or mica crystals present helps to identify met. rocks
Metamorphic Rocks are classified into two groups.
1. Foliated: _____________________________________
_____________________________________
__________.
Alignment of minerals or the separation of
minerals into platy (flaky) layers of light and
dark bands
Foliation commonly appears as _______. Banding
Generally the more intense the temperature and
pressure, the thicker the mineral bands will be.
Thick banding indicates a high degree of
metamorphism.
Notice how your ESRT’s shows
banding?
2. Non Foliated: _____________________________
____________________________________.
Rocks that generally have uniform
Composition (little or no grain arrangement)
Non foliated rocks DO NOT have bands
Form as a result of equal pressure being applied in all
Directions OR contact with hot rock.
Pressure equal in
all directions
Ex: __________________ Quartzite and Marble
1. Contact (Thermal) Metamorphism
Occurs where: ___________________________________
___________.
Molten magma (lava) comes in contact with
other rocks
***The rocks are “cooked” but not melted.*** Contact metamorphism occurs over a small area.
Ex: ___________________________________________ Vein of magma (dike) or around a magma chamber Vein of magma is hot!!!
Contact Metamorphism
Two Types of Metamorphism:
Transition Zone -gradual change from original unaltered rock to altered metamorphic
Any rock can undergo contact metamorphism as long as the heat is strong enough.
2. Regional Metamorphism
Occurs at: ______________________________________
______________________________________.
Margins of continents where the rock is deeply
buried and exposed to extremely high pressures
Ex: ________________________________________ Continental Collision and Bottom of Lithosphere
Regional metamorphism
occurs here over a large area
Regional
metamorphism
is associated
with orogeny
or mountain
building
processes.
Name Metamorphic Rock produced
from each Parent Rock • Shale Slate
• Sandstone Quartzite
• Limestone Marble
• Dolostone Marble
• Conglomerate Metaconglomerate
• Granite Gneiss
Different metamorphic rocks may be formed from the
same parent rock depending upon the pressure and
temperature in the environment in which it forms.
Ex: ________________________ Gneiss, Schist, and Phyllite
Different metamorphic rocks can be formed from the same parent
rock depending on the degree of Metamorphism in which it formed.
For example:
Shale + H/P Slate + H/P Phyllite + H/P Schist + H/P Gneiss
Depends on Degree of
Metamorphism
VI. Distribution of Rock Types
a) Covers continent as thin layer or veneer? • Sedimentary
b) Found at or near surface of volcanoes and mountains?
• Igneous
c) How are intrusive igneous and metamorphic rocks found at Earth’s surface instead of deep below?
• Forces have pushed these rocks upward towards the surface
Rock Cycle Objective
• #10. Be able to interpret the Rock Cycle
diagram on page 6 of the ESRT.
Row, Row, Row Your Rocks
• Sedimentary rocks, mostly found in layers
• Often found near water sources with fossils from
decayers
• Then there's igneous rock here since earth was
born
• Molten lava crystallized and that's how they form
• Metamorphic rocks come from rocks that change
• Pressure, heat, and chemicals atoms rearrange
• Rocks changing back and forth a never ending
story
• So many things to know rocks are never boring
C The Rock Cycle The Rock Cycle is: ______________________________________
________________________. A model to show all possible changes that
rocks can go through.
The amount of rock material on Earth remains constant , with
the exception of ___________________
___________________.
Extraterrestrial material
from space (Meteorite)
Any type of rock, Igneous, Sedimentary, or Metamorphic,
may be changed into any other type depending upon the
environment to which it is subjected.
There is no preferred or predictable path that a rock will take
within the environment.
ESRT Page 6
1. List 3 processes needed for an igneous rock to become sedimentary.
2. What must happen to a sedimentary rock to make it metamorphic?
3. What’s one word that all rocks are called before they become igneous rock?
Rock/Mineral Resource Objectives
• #11. What are fossil fuels and how do they
impact our society?
• #12. Why is the conservation of minerals
and resources important?
D. Environment of Rock Formation & Use depend on composition, structure and texture
• Granite-
– takes polishing, used for monuments & buildings
• Gabbro-
– large dark crystals, used for road base
• Sandstone-
– layers, used for building, “blocks”
• Slate-
– easy to cut, used for roofing tiles, flagstone, & pool tables
• Marble-
– nonfoliated, used for statues & ornaments
Useful properties of Rocks & Minerals include:
•Stone for building materials:
•Roads
•Buildings
•Making concrete
Land Use and Rocks • What humans can do in a given geographic
area often depends on the local bedrock.
– Limestone rock for farming
– Granite & gneisses make great bedrock for
skyscrapers! (think NYC)
– Some igneous/metamorphic bedrock forms
thins soil and is almost impossible to grow food
on. (think Adirondacks Mts.)
E. Resource Conservation
• With the Earth’s population rapidly increasing,
the demand for energy and resources is rapidly
increasing as well.
• Direct Relationship
Earth’s Population
Dem
an
d f
or
En
ergy
& R
esou
rces
At the present time, fossil fuels are primary source of ______. energy
Fossil fuels and most minerals are ____________________
because _____________________________________.
Nonrenewable resources
they are being used faster than they can form
Fossil fuels- Hydrocarbon deposit in Earth formed from
organic matter in the past such as coal, oil, and
natural gas.
Fossil Fuels: • Coal, oil and natural gas
provide most of the worlds
energy.
• These “fossil fuels” are
nonrenewable in our
lifetimes.
• Means we are using them
faster than they can be
made/replaced
• What will we do when
they become too scarce to
obtain???
Fossil Fuels
• Beside being used for energy, also used to
make plastics, medicines, cosmetics,
fabrics, etc.
• With such a demand on fossil fuels, some countries have become wealthy due their fossil fuel reserves.
• Uneven distribution of resources and increasing demand for dwindling resources results in higher prices which alters many peoples standard of living (either for the better or the worse) and in the past has even resulted in wars.
Minerals and Humans:
Humans have designed an entire economy around minerals! Without them, our lives would look completely different! Imagine:
• No electronics (cell phones, TV, video)
• No gemstones
• No pencil graphite or lead
• No cosmetics (sorry girls)
• No automobiles, bicycles, etc…..
• The list could go on and on….
•Metals for:
•Electronics
•Building materials (structural steel)
•Investment (gold, silver, platinum)
•Minerals for:
•Just about everything not plastic!
•Gemstones (jewelry & investment)
Global Distribution: • Minerals can only be mined wherever they are
found! Often, mineral resources are found only in
remote, hard-to-reach places.
How can we reduce the current usage rate of our natural resources?
1. _____________________________________________________
2. _____________________________________________________
_______________________________________
3. _____________________________________________________
Finding and using alternative energy sources (Solar, Hydropower,
Wind, Geothermal, and Nuclear Energy)
Practice the 4 R’s (Reduce, Reuse, Recycle, Reclaim)
Replace inefficient technology with superior technology