Final Rocks and Minerals 2015 student edition

9/17/15
I Can…..”
Identify the
differences
between a
mineral and
a rock.
What is a mineral?
A mineral:
o  Is a Inorganic solid formed in nature
(Inorganic -- not living or ever been
living. Which means that it is not
formed by plants or animals)
o  Has a “fixed” chemical composition
o  Has distinctive physical properties
o  Has a Crystalline structure (has an
orderly arrangement of its atoms)
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Crystals:
•  Minerals with some solid, geometric shape to
them are called crystals. They are produced by
a repeating pattern of atoms that is present
through-out the mineral.
Crystals can be made from different elements:
(ex: diamonds –are made from the element
Carbon)
(salt—is made from the element Sodium and
Chlorine)
Crystals:
•  A crystal’s shape is determined by the
arrangement of the atoms within the crystal.
•  A crystal’s color is determined by the elements
that are mixed in it.
•  Crystals are not just what we think of as
jewelry. You actually eat many different types
of crystals! ( such as salt, sugar, baking soda)
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Minerals are more common than
you think…
•  Currently, about 4,000 minerals
have been identified, and 50 to
100 new minerals are discovered
each year!!
•  We use them in our everyday
households such as metal pots
and pans, salt shakers, dishware,
and even glassware!!!
How do minerals form?
•  They form in several ways:
1.  From melted rock inside the Earth called magma
As it cools the atoms combine in orderly patterns to
form minerals
2.  From magma that reaches Earth’s surface, called
lava. As it cools the atoms combine in orderly
patterns to form minerals
3.  Evaporation of dissolved minerals
4.  From precipitation *water in the atmosphere can hold
the dissolved minerals that have “evaporated”.
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Properties of Minerals include:
•  Color
Luster
•  Streak
Hardness
•  Cleavage & Fracture
•  Density
•  Specific Gravity
•  Special Properties
Color: Not Mineral Specific
Color is the LEAST reliable way to classify a mineral.
A certain mineral may form in many different colors due
to any chemical impurities it may contain that will affect
the mineral’s color! *See examples of Quartz below:(A) clear Quartz
(B) Blue Agate, (C) Rose Quartz, & (D) purple Amethyst.
Purple due to
small amounts
of Iron
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Other factors can also affect a mineral’s color. Weathering changes the
surface of a mineral which slightly affects the color. Because color
alone is “unreliable”, geologists rarely identify a mineral just on its
color. To identify most minerals, they must use several properties.
Luster: (shininess) Describes how light reflects off of the
surface of a mineral. You might describe diamonds as
sparkly or pyrite as shiny. But mineralogists have special
terms to describe luster. They first divide minerals into
metallic and non-metallic luster.
Metallic
Non-metallic
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IV. Shininess (continued)…
Luster (or shininess) can be either:
Metallic – shines like metal
Non-metallic – dull, pearly, earth
(A) Diamonds have an adamantine luster (transparent &
highly reflective. (B) Kaolinite is a clay with a dull or
earthy luster. (C) Opal’s luster is greasy.
(D) Chalcopyrite has metallic luster. (E) Stilbite has a
resinous luster. (F) The white ulexite has silky luster.
(G) Sphalerite has a submetallic luster. (H) Jade is a
mineral with a waxy luster.
of the powder of a mineral. To
Streak: Is dotheacolor
streak test, you scrape the mineral
across an unglazed porcelain plate.
NOTE: The color of the streak often differs from the
color of the larger mineral sample, Different minerals
may be the same color, but they may have a different
color streak! The color of a mineral may vary BUT
streak does not!
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Cleavage & Fracture
Describes how different types of minerals break.
Cleavage is the tendency of some minerals to break
along smooth, flat surfaces.
Fracture is the tendency
of some minerals to break
unevenly along curved or
irregular surfaces
Mica
Hardness: A mineral’s resistance to being scratched.
Minerals that are not easily scratched are considered “hard
minerals” and those that are easily scratched are considered
“soft minerals”. This is tested using the Mohs Hardness
Scale. You test the hardness of an unknown mineral by
scratching its surface with a mineral of a known hardness.
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As you can see, diamond is a 10 on the Mohs Hardness Scale. Diamond is the
hardest mineral; no other mineral can scratch a diamond. Quartz is a 7. It can
be scratched by topaz, corundum, and diamond. Quartz will scratch minerals
that have a lower number on the scale. Fluorite is one. Suppose you had a
piece of pure gold. You find that calcite scratches the gold. Gypsum does not.
Gypsum has a hardness of 2 and calcite is a 3. That means the hardness of
gold is between gypsum and calcite. So the hardness of gold is about 2.5 on
the scale. A hardness of 2.5 means that gold is a relatively soft mineral. It is
only about as hard as your fingernail!
Oohhhhhh Diamonds!...
• 
• 
• 
• 
• 
• 
Diamonds are the hardest known mineral (10 on Mohs’
Hardness Scale)
They are formed very deep in the Earth and at great
pressure.
It takes 250 tons of Earth to obtain a 1.00 Ct Diamond!
It takes 1405 degrees of heat to burn a Diamond!
Only Diamonds can Scratch or Polish another Diamond!
Diamonds come in wonderful fancy colors like, Pink, Blue,
Green, Champagne, Black, Chocolate, Yellow, Red, Gray,
and even Purples!
(Here is the famous HOPE diamond,
which is blue!!)
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Did You Know?
The largest diamond in the world is the Cullinan diamond
weighing 3,106 carats! It was cut into 105 separate diamonds.
Oohhhhhh Diamonds!...
•  If Diamonds are the hardest mineral,
what is the second hardest mineral
according to the Mohs Hardness
Scale?
•  Corundum!!!! Which is the
mineral name for ruby and
sapphire.
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Density
Density describes how much matter is in a certain
amount of space. Substances that have more matter
packed into a given space have higher densities.
Mass is a measure of the amount of matter in an
object. The amount of space an object takes up is
described by its volume. The density of an object
depends on its mass and its volume. Density can be
calculated using the following formula:
Density= Mass/Volume
• Different minerals have different densities.
Special Properties
•  Some properties are “special” because they
only belong to a few types of minerals!
*Magnetite
*Uraninite
*Some minerals have a distinctive smell: Sulfur (smells like rotten eggs)
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GEMS……
• 
• 
• 
• 
are rare minerals that can be cut and polished,
giving them a beautiful appearance.
Ideal for jewelry
Are “rare” and are therefore “valuable”
Are created by tremendous amounts of heat and
pressure, deep in the Earth’s mantle
It takes a certain kind of volcanic eruption to
bring diamonds close to the surface
Ores……
A mineral is called an ore if it contains enough of a useful
substance that it can be sold for a profit.
Metals that people use, such as:
•  Iron used to make steel comes from Hematite
•  Lead for batteries comes from Galena
•  Magnesium in vitamins comes from Dolamite
• 
In order to obtain these ores, they must be mined
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Minerals Review….
• Now watch the Mineral’s
Review Quiz. See if you can
classify the following items
correctly.
•  (Use your half-slip we pasted in
your ISN.)
What is a Mineral?
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What is a mineral?
A mineral is a naturally formed, inorganic solid that has a definite crystalline structure. It has to pass the SNIFC test..
– Solid •  Cannot be a liquid or a gas – Naturally Occurring •  Found in nature, not man-­‐made – Inorganic •  Is not living nor has ever been living – Fixed chemical composition •  Has a definite chemical formula, most are formed from two or more elements, but some minerals consist of one element ex. Au – Crystalline structure •  A definite structure in which atoms are arranged in a geometric pattern 13
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Questions to ask yourself when
determining if an item is a mineral or not:
–  Is it non-­‐living material? –  Is it a solid? –  Is it formed in nature? –  Does it have a crystalline structure? Wood
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Gold Fossil 15
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Topaz Bones 16
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Granite Quartz 17
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Pearls Talc 18
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Icebergs Diamond 19
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Coal Rock Salt 20
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And How
the answers
are…
did you do?....
•  Minerals a) 
b) 
c) 
d) 
e) 
f) 
Gold Topaz Quartz Talc Iceberg* Diamonds •  Non-­‐Minerals a) 
b) 
c) 
d) 
e) 
f) 
g) 
Wood -­‐ once living Fossils – once living Bone -­‐ living material Granite -­‐ intrusive igneous rock Pearls – made by oysters Coal -­‐ Sedimentary rock Rock Salt – Sedimentary rock FYI: According to the IMA (International Mineral Association) – ice is listed
as a mineral!
Quick Check…..
• Can you
name all
eight
physical
properties of
minerals?
• 
• 
• 
• 
• 
• 
• 
• 
Color
Luster
Streak
Hardness
Cleavage & Fracture
Density
Specific Gravity
Special Properties
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I Can…..”
explain how
the three
different
types of rocks
are formed .
So What Exactly is a Rock??
A rock is a naturally occurring solid
mixture of one or more minerals and
“organic” matter. *organic = living
Rocks go through a “cycle”, meaning
they are constantly changing into
different forms.
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Classifying Rocks
•  Each class of rock can be divided further and classified
based on differences in the ways rocks form.
•  Igneous rock can be divided again based on whether the
magma from which it forms cools is on the Earth’s
surface or underneath the ground.
•  Sedimentary and metamorphic rocks are also divided
into smaller groups.
•  Scientists study rocks in detail using two important
criteria: composition and texture.
What determines a rock’s composition?
•  The minerals that a rock contains determine the ”Composition”
which is the combination of substances that are contained in rock.
• 
(ex: a rock made mostly of quartz will have a composition similar to Quartz.
But a rock made of 50% quartz and 50% feldspar will look much different than
that of pure Quartz)
• 
Quartz
& Feldspar
Quartz
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Rocks have Quality!!!
• Texture is the size, shape, and position of the rock’s
grains. It’s what determines the “quality” of a rock.
Texture provides clues as to “how” and “where”
the rock actually formed and reveals the process
that formed it.
Siltstone
Fine grained
Sandstone
Medium grained
Conglomerate
Coarse-grained
3 Major Types of Rocks
Igneous Rocks
Metamorphic Rocks
Sedimentary Rocks
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Look at these pictures of rocks. • How are they different?
• How are they the same?
Igneous Rocks
Igneous Rocks are called
“fire rocks”
The word “ignis”
means “fire” :
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How are igneous rocks formed?
Name two places where igneous rocks form
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Igneous rocks are made either
underground (intrusive) or
above ground (extrusive).
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Igneous Rocks – ‘fire rocks’
•  Underground: melted
rock, called magma, cools
slowly and solidifies to
become igneous rocks. Igneous Rocks – ‘fire rocks’
•  Above ground:
volcanoes erupt,
bringing the
magma to the
earth's surface,
it is called lava.
The lava cools
and becomes
igneous rocks.
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What determines crystal size?
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What’s the difference between
extrusive and intrusive igneous rocks?
form on or near the
surface
(small crystals)
form below the
surface
(large crystals)
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Characteristics used to classify igneous rocks
Characteristics used to classify igneous rocks
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Characteristics used to classify igneous rocks
Characteristics used to classify igneous rocks
Helps determine the color of the
melted rock.
This depends on the materials
that were available as the rock
was forming.
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Igneous Rocks – ‘fire rocks’
Granite
Pumice
Basalt
Obsidian
Pumice is cool! It can float!
u  Pumice
– used for cleaning and polishing
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Uses of Igneous Rocks
•  Statues and Public Buildings -
Uses of Igneous Rocks
•  Cobblestone streets and Granite kitchen
countertops – Granite
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Sedimentary Rocks
“Sandwich rocks”
Sedimentary Rocks
“sandwich rocks”
•  For millions of
years, little pieces of
our earth (called
particles) have been
broken down by
wind and water. 36
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Sedimentary Rock
“sandwich rocks”
•  These little bits of
our earth are
washed to the
bottom of the rivers,
lakes, and oceans
where they settle and
are compressed
together over time. Sedimentary Rock
“sandwich rocks”
•  Many layers of small pieces of earth collect on top of
each other in layers. These layers are pressed down
more and more until the bottom layers slowly turn into
hard rock.
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4 Steps in which Sedimentary
Rocks are Formed
• 
• 
• 
• 
Wind and water break down the earth
Bits of earth settle in lakes and rivers
Layers are formed and build up
Pressure and time turn the layers into rock
There are 4 main processes needed to form sedimentary rock: Step 1: EROSION (par8cles wash away) Forces of running water, wind, or ice that loosen & carry away fragments of rock Can you see the sediment moving in the water? Have you ever seen sediments being moved during a hard rain? 38
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There are 4 main processes needed to form sedimentary rock: Step 2: DEPOSITION (deposits -­‐ drops down) Sediments se@le out of the water or wind carrying them & se)le to the bo@om of a lake or ocean. Sediments move down the sloped land & seFle at the boFom. Over 8me these sediments layer up. There are 4 main processes needed to form sedimentary rock: Step 3: COMPACTION (smashed together) Process that presses sediments together. Thick layers of sediment build up over Ime & weigh down the layers compac.ng them. 39
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Those smashed sediments can form into layers like the ones shown above. There are 4 main processes needed to form sedimentary rock: Step 4: CEMENTATION (glued together) Dissolved minerals seep into spaces between parIcles (sediments) & then crystallize as they harden. 40
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Sedimentary Rock
•  These 4 processes can take
thousands to millions of years
to form.
The most common form of sedimentary rock on
Earth is “Shale”.
It covers about ¾ of the land’s surface.
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Most sedimentary rocks are made of pieces:
of other rocks.
Remains of living things.
Minerals that are dissolved in watery
solutions
Made from pieces of other rocks
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Made from remains of living
things (fossils)….
Made from minerals that are
dissolved from “watery solutions”….
Rainwater
makes it way to
the oceans
dissolving
minerals along
the way.
Ex: rock salt
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Types of Sedimentary Rocks
Sandstone
Limestone
Conglomerate
Shale
Metamorphic Rocks
“changing rocks”
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Metamorphic Rock – ‘changing rocks’
Metamorphic rocks are rocks that have
"morphed" or changed into another type
of rock. The word metamorphic means
“changed form”. These rocks were once
either igneous or sedimentary rocks.
Metamorphic Rock – ‘changing rock’
•  They are formed from extreme heat and
tons of pressure 45
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Two types of texture in
Metamorphic Rock:
Foliated
•  Contains minerals
that have been
aligned by
pressure and
almost look like
pages in a book.
Nonfoliated
•  Do not have
distinctive layers
and Are made of
only a few minerals:
•  Ex: Slate
Metamorphic Rock – ‘changing rock’
•  Most rocks will melt at temperatures
higher than 1,000 degrees Celsius_. 46
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Under pressure and
Feeling the Heat!!!
(Horseshoe shaped)
Metamorphic rock is like
plastic!!
•  When rocks metamorphose
under high temperature and
pressure, they become plastic
and can be easily deformed.
The largest range of exposed
metamorphic rock in the
world is the Canadian Shield.
It is the source of more than
70% of the minerals mined in
Canada.
Texture of Metamorphic
Rock…
Foliated metamorphic rock:
The hot minerals become aligned by pressure and
almost look like pages in a book. *banded
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Texture of Metamorphic
Rock…
Nonfoliated metamorphic rock:
Do not have distinctive layers and are made of
only just a few minerals.
Types of
Metamorphic Rocks
Schist
Gneiss
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Metamorphic Rock “changing rock”
Marble
Slate
Quartzite
I Can…..”
identify the
major processes
that explain the
rock cycle.
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The
Rock
”Cycle” ☺
Rocks and the Rock Cycle…
Remember rocks go through a
“cycle”, meaning rocks are
always changing. New rocks
continually form from old rocks
and old rocks get recycled. We
call this process process the
“Rock Cycle”. This process is
similar to other cycles we know
of such as the water cycle,
carbon cycle, and nitrogen
cycle.
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The Value of Rock
•  Rock has been an important natural resource
for as long as humans have existed.
•  Ancient and modern civilizations have used
granite, limestone, marble sandstone, slate and
other rocks as construction materials.
•  Rock is also an important ingredient in
concrete and plaster, both of which are
commonly used in construction.
Processes That Shape the Earth
Certain geological processes make and
destroy rock.
•  These processes have shaped the
features of our planet.
•  These processes also influence the
type of rock that will be found in
certain areas.
• 
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Processes That Shape the Earth
include:
• 
• Weathering
• Erosion
• Deposition
• Lithification
• .
Weathering, Erosion, and Deposition
• The process in which water, wind, ice, and heat break
down rock is called weathering.
•  Weathering is important because it breaks down rock
into fragments from which sedimentary rock is made.
•  Wind, water, ice, and gravity then transports soil
and sediment from one location to another through a
process called erosion.
•  As the process continues sediments are later moved
by erosion and eventually dropped and comes to rest in
a process called deposition.
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Processes That Shape the Earth, continued
As rock particles and organic matter are eroded to
a place of deposition and are covered by additional
particles, eventually the weight from above will start
a process called lithification.
Lithification involves two steps:
A) compaction --squeezes out the fluids and
space that exist between the particles.
B) cementation--- results when the fluids that are
squeezed out are replaced with minerals that
were in the fluids.
**Once cementation occurs, the new sedimentary
rock has been formed
From Sedimentary Rock to Metamorphic
•  Temperature and pressure are important:
• If the heat and pressure are high enough, the rock
can change into metamorphic rock.
•  If the rock gets hot enough to melt, this creates the
magma that eventually cools to form igneous rock.
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How the Cycle continues:
•  Rock that is buried beneath the earth’s crust is
eventually uplifted to the surface thanks to
movements within the Earth . This process is
called “uplifting”.
•  As Erosion continues to chip away at the Earth’s
surface , the rock that has been uplifted will
eventually be exposed to the Earth’s surface.
When uplifted rock reaches the Earth’s surface,
weathering, erosion, and deposition begin to help the
cycle begin all over again.
What happens to older rock?????
• As new rock is pushed
up towards the surface,
older rock is pushed
down!!.
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Rock formation does not have to
go through a direct pattern.
• Understand that sedimentary rock can become
igneous rock just as metamorphic rock can become
sedimentary rock!!
• Remember:
• The rock cycle is not an overnight process. It may
take millions to tens of millions of years for each
process in the rock cycle to occur!!!.
The Rock Cycle in Action:
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