Transcript Rocks & Minerals

Rocks&&MINERALS
Minerals
ROCKS
Minerals
EQ:
How are minerals a part of rocks?
What is a Mineral?
• DEF: A naturally occurring,
inorganic solid that has a
crystal structure & a definite
chemical composition.
• Example: Quartz
Minerals must be:
• Naturally occurring
made from nonliving things
(fossils & coal are made
from living things that
died so are not
considered minerals)
Not man made
Naturally-occurring
• Never man-made
• Ex: Like rocks
Inorganic:
• Means the mineral cannot come
from things that were once living
• Non Example: Coal – it is organic
because it comes from plants that
lived millions of years ago.
Solid
 A 3-D geometric figure
 Not a liquid or a gas!
Minerals must be:
• Solid
– Have a fixed shape
and volume
– Never livinginorganic
Crystal:
 The repeating pattern of
particles, line up when they
form
 Like a snowflake pattern or
rock candy
6 Different Crystal Systems:
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Cubic
Hexagonal
Tetragonal
Orthorhombic
Monoclinic
Triclinic
Ex: Magnetite
Ex: Quartz
Ex: Rutile
Ex: Sulfur
Ex: Azurite
Ex: Microcline
Feldspar
Minerals must have:
• Have a definite
crystal structure
– particles line up in a
regular, repeating
pattern.
– flat sides called faces,
that meet at sharp
edges and corners.
http://vasichkominerals.com/
Minerals must have:
• A definite
chemical
composition
– Always contains
certain elements in
the same proportion.
http://www.eas.slu.edu/People/Students/woodhull/uraninite.html
– Almost all minerals
are compounds, (two
or more different
elements chemically
joined).
Definite Chemical Composition
 Certain elements form together in
specific ways
 Like Hydrogen & Oxygen (H2O) and
Carbon & Oxygen (CO2) form
together to make these compounds
Minerals Review
• All minerals
must:
– Occur naturally
in nature
– Inorganic solid
– Crystal structure
– Definite
chemical
composition
http://nature.ca/museum/press/2006/pr06-02-07_minstucson_e.cfm
Physical Properties Identify
Minerals
 Physical Properties include 6
“tests” you can perform on
minerals to determine what
type of mineral they might be.
Properties of Minerals
• Color
first thing noticed
about minerals
http://www.nmnh.si.edu/rtp/students/2004/virtualposters/poster
1. Streak Test
 The color of the mineral’s powder
that’s left behind when it is
rubbed across a rough surface
 Example: Pyrite looks like gold
but, it’s streak looks greenishblack
(aka “fool’s gold”)
Properties of Minerals
• Streak
• The color of its
powder.
• Not always the same
as the color of the
mineral.
http://geology.csupomona.edu/alert/mineral/streak.htm
2. Luster
 Describes how light is reflected from
the mineral’s surface. What does it
look like?
Properties of Minerals
• Luster
• The way a mineral
reflects light.
• Can be metallic or
non-metallic.
• Shiny or dull.
• waxy, pearly, glassy.
This is a gem stone called
tourmaline it has a glassy
luster
Types of Luster
– Metallic
– Glassy
– Waxy, Greasy, Pearly
– Dull
– Silky
– Earthy
Ex: Galena
Ex: Topaz
Ex: Talc
Ex: Graphite
Ex: Malachite
Ex: Hematite
3. Density
 It’s a calculation
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(math problem!)
Use a balance to find the mass
Place the mineral in H2O to find the
amount of water it displaces. This
amount is the volume of the mineral.
To find the density, divide mass by
volume
Ex: Sample of Olivine
 Mass = 237 g Volume = 72 cm3
 Density = 237 g/ 72 cm3 = 3.3 g/cm3
Properties of Minerals
• Density
• Minerals will have a
certain density
regardless of the size of
the sample.
• Each mineral has its
own density called
specific gravity
http://www.astronomynotes.com/cosmolgy/
4. Cleavage
 One way minerals break
 Easily split along flat surfaces
 Ex: Mica & Feldspar
5. Fracture
 One way minerals break
 Break unevenly in irregular ways
 Chipped
 Shell-like
Ex: Quartz
 Jagged points
Ex: Copper & Iron
 Crumbles
Ex: Clay
6. Mohs Hardness Scale
 A scale that ranks 10 minerals from softest to
hardest. You can compare unknown minerals
to the minerals on this scale
 Hardness can be tested by a Scratch Test
 A mineral can scratch any other softer mineral
 It can also BE scratched by any harder mineral
 Softest Mineral – Talc
 Hardest Mineral - Diamond
Properties of Minerals
• Hardness
A measure of how
easily a mineral can be
scratched.
http://www.info-diamond.co.uk
Rocks classification
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http://geology.com/rock-tumbler/tumbling-rough.shtml
Texture
Grain
Minerals
Color
Origin of rocks
Rock classification
• Texture is how a rock
looks and feels
• texture in rocks is
determined by the
size, shape, and
pattern of a rocks
grains.
ocal.wasp.uwa.edu.au/.../rock/rock16.jpeg
Rock Classification
• Grain
– Size -- large, small
– Shape --smooth, rough,
round jagged
– Pattern – rows, waves,
swirls, beads or
random patterns
http://www.union.edu/PUBLIC/GEODEPT/COURSES/geo-10/metamorphic.htm
Rock classification
• Mineral
composition
– Rocks are made of
more than one
mineral
blue.utb.edu/.../PHYS1417SPR00/Unit3Lec.html
Rock classification
Rocks & Minerals
• Color rocks
come in all sorts
of colors
Rock Classification
• Origin of rocks
• How were the
rocks formed
- magma
- erosion and
layering
- heat and pressure
Origin of rocks
• Igneous rocks are
formed from the
cooling of magma or
lava
– Lava is magma that
reaches the earth’s
surface
www.outreach.canterbury.ac.nz/.../igneous.jpg
Origin of rocks
• Sedimentary rocks
are formed from other
rocks that are broken
into small particles
and moved by erosion
(wind or water)
• The particles are
squeezed or cemented
together
• Rocks are layered
www.energyinst.org.uk/education/glossary/
Origin of rocks
• Metamorphic rocks
are formed from other
rocks
• Rocks have been
pushed deep into the
earth’s crust
• Pressure from the
earth above and heat
from the mantle below
cause them to change
shape, color, grain and
crystal structure
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0607/es06
07page01.cfm?chapter_no=visualization
Rock cycle
http://www.classzone.com/books/earth_science/terc/content/investigati
ons/es0602/es0602page02.cfm