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Minerals
Section 4.1
Why Are Mineral’s
Important?
“Minerals play important roles in
forming rocks…and continue to play a
role in shaping civilization”
-Calcite is the mineral that forms the 2
million limestone blocks that make up
the Great Pyramid in Egypt.
-Wars have been fought and empires
have crumbled over minerals such s
gold and silver.
Quick History Lesson
• http://www.youtube.com/watch?v=rjhIzemLd
os
What is A Mineral? How are they
different from rocks?
• A mineral is a naturally
occurring, inorganic
solid with a specific
chemical composition
and a definite
crystalline structure.
• A rock is a naturally
occurring aggregate of
minerals
and/or mineraloids.
Rocks do not have a
definite chemical
composition.
• For example: Gabbro
has plagiocase,
pyroxene, olivine (all
minerals).
What Do You Mean Naturally
Occurring?
• It mean’s cannot be created in a lab. That
means synthetic diamonds that are created in
a lab cannot be minerals.
• Most natural diamonds are formed at high
temperature and pressure at depths of 140 to
190 kilometers (87 to 118 mi) in the Earth's
mantle.
Mineral Characteristics (Slide 1)
• All minerals are
naturally occurring by
natural processes.
Substances created in a
lab are not minerals.
• Second, all minerals are
inorganic. That is, they
aren’t alive and never
were during their
existence. (Let’s talk
about coal).
Coal Does Not Fit. Why?
• Coal is formed by ancient plants and animals
accumulating in moist peat bogs. As plants die off
in a wet area, they pile up into peat. It takes
between 4,000 and 100,000 years for one meter
of peat to accumulate. This process happens best
in river deltas or coastal plains.
• Over time, these peat seams are compressed by
further deposits and the carbon content of the
coal is concentrated. The older the coal gets,
generally, the harder and blacker it gets.
Mineral Characteristic’s (Slide 2)
Solid’s With Specific
Compositions
• -Solids have definite shapes,
gas and liquids do not.
• -Each type of mineral has a
chemical composition
unique to the mineral. Most
consists of a combination of
elements, while others (like
Silver) are composed of a
single element.
-Quartz
• A combination of two
oxygen atoms and one atom
of silicone.
Mineral Characteristics (Slide 3)
Definite Crystalline Structure
• The atoms in minerals are
arranged in geometric
patterns that are repeated
over and over again.
• Unfortunately, well defined
crystal shapes shown in the
examples are very rare.
Why? Most minerals are
formed in restricted spaces.
Crystal Systems
Important Mineral Groups To Know
• Silicates: Oxygen is the most abundant element in
earth’s crust, followed by silicon Minerals that
contain silicon and oxygen (and other elements)
are known as silicates. Examples are Quartz and
Feldspar.
• Carbonates: Carbonates are minerals composed
of one or more metallic elements with the
carbonate compound CO3
• Oxides: Oxides are compounds of oxygen and a
metal. Hematite (Fe2O3) and Magnetite (Fe3O4)
are examples of oxides.
Elements In Earth’s Crust
End of Section 4.1
Minerals
Section 4.2
Mineral Identification
• Geologist rely on several simple test to identify
the minerals.
• Color: Most noticeable characteristic, but the
least reliable to use on it’s own. To many
variables to depend totally on color.
• Luster: The way light reflects on a mineral is
called luster. Luster is described as metallic and
non-metallic. Silver, gold, copper, etc have shiny
surfaces. Non-metallic minerals, such as calcite,
gypsum, and sulfur do not.
Mineral Identification
• Texture: Describes how a mineral feels to touch.
Smooth, rough, ragged, rusty, etc. Also rarely
used on it’s own.
• Streak: Is the color of a mineral when it is broken
up and powdered.
• Hardness: Is a measure of how easily a mineral
can be scratched on of the most useful ways to
identify a mineral.
• Cleavage: Minerals break along planes where
atomic bonding is weak. (Will go over in the
video).
Mineral Identification
• Density and Specific Gravity (Will not be
included on any test): Give the pyrite and gold
example on the board.
• Density is the mass of the substance divided
by the volume.
• Specific Gravity is the ratio of the weight of a
substance to the weight of an equal volume at
water at 4 (celcius)
Mineral Identification Video
• http://www.youtube.com/watch?v=c7wJP_K_
sAQ
End of Chapter 4/ Final Question
• How can minerals be used for human use?
Give some examples.