Download Minerals

Be sure to get your daily dose.
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They occur naturally in the Earth’s crust.
They are inorganic.
They are solid.
They possess a definite chemical structure.
Rocks are simply aggregates of two or more
minerals.
There exist roughly 4000 known minerals.
Most minerals are comprised of two or more
elements.
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Atoms are the smallest particle that has all the
characteristics of an element.
Atoms are made of subatomic particles.
Protons – found in nucleus, 1 AMU, (+)
Neutrons – found in nucleus, 1 AMU, neutral
Electrons – orbiting nucleus, 1/1836 AMU, (-)
Ions have gained or lost electrons
Isotopes carry varying number of neutrons.
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Crystal form – the external expression of the
internal orderly arrangement of atoms.
Without space limitations, crystals are readily
apparent. (example – Quartz)
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When space is limited, crystalline form is not
readily apparent and takes on a different
appearance. (example – Granite)
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Luster describes the appearance or quality of
light reflected from the surface of a mineral.
Luster is described as metallic or non-metallic.
Metallic – (example Pyrite, eg: “Fool’s Gold”)
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Non-metallic minerals are described as:
Vitreous (glassy, example – Quartz, used in jewelry
and time-keeping)
Pearly (example – Muskovite, used in jewelry, clothing
accessories, and cosmetics)
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Silky (example – Calcite, used in cosmetics)
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Resinous (example – Amber, used in jewelry)
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Earthy (dull, example – Chrysocolla, used in
jewelry and cosmetics)
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Color is an unreliable way of classifying to the
untrained eye. Some minerals may exhibit
varying colors depending on concentration of
elements. (example – Quartz)
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Streak is the color of a mineral in its powdered
form. This indicator is much more reliable than
“color”.
Streak is obtained by rubbing the mineral
across a piece of hard, unglazed porcelain.
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Mineral hardness is measured on a Mohs scale.
The scale uses known and well-established
standards of hardness and a comparison is
drawn using the sample.
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Because some bonds in crystals are weaker than other
bonds, minerals can be broken (cleaved) along planes
formed by these weak bonds.
Not all minerals are prone to cleavage. Those that are
break in such a way that they can be readily identified.
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Minerals can break in ways other than along planes
caused by weak bonds.
These breaks are known as “fractures”.
These fractures can be curved (glass) or splintered
(asbestos). Most fractures in minerals are irregular.
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Comparison between the density of a mineral
to the density of fresh water.
If the density of a mineral is twice that of fresh
water, the specific gravity of that mineral is 2.
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Of more than 4000 minerals identified, no more than a
few dozen are considered abundant.
In fact, only 8 elements compose the bulk of these
minerals and account for more than 98% (by weight) of
the Earth’s crust. The minerals are called “rockforming”.
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Silicates – comprised of combinations of
Silicon and Oxygen atoms. This group is
the most common mineral group.
Other than a few “pure” silicates (like
quartz), silicates are electrically neutral.
 Uses include lenses, gauges, adhesives, and
many manufacturing processes.
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Carbonates – comprised of combinations of
Carbon and Oxygen atoms.
These rock-forming minerals make up about ¼
of the Earth’s crust. But, they are economically
important.
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Calcite makes up the bulk of carbonates and is the
basis for rocks like limestone and marble.
Halite (table salt) and Gypsum (used in wallboard)
are two common carbonates.
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Reserves are identified deposits from which
minerals can be profitably extracted.
Ores are useful metallic minerals that can be
profitably extracted.
Non-metallic minerals used as building
materials, abrasives, fertilizers, etc. are
identified as industrial rocks and minerals.
Although these minerals occur naturally, they
are typically not economically feasible as a
resource unless they are refined (concentrated).
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Mining is used to extract minerals from the Earth’s
crust.
Shaft, Slope, Drift, and Open-Pit mines have been used
to obtain minerals.
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Bingham Canyon Copper Mine, near Salt Lake
City, UT.
Over 2.5 miles across and almost 1 mile deep.
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Historically, machinery was on a “human
scale”.
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Draglines are used to remove ore from the mine floor.
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Trucks used to move mined ore to surface.