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Chapter 3-1
Minerals Study Guide
Ms. Grady
Minerals – →
A mineral is a naturally occurring,
inorganic solid that has a definite
chemical composition and crystal
structure.
 A mineral has an orderly
arrangement of atoms.
Summary of Characteristics of Minerals
 Naturally occurring
 Inorganic Solid
 Definite chemical composition
Ex, halite →NaCl
 Crystal Structure
 Pattern of atoms repeated
*Naturally = not artificial or synthetic
Minerals or Not???
Yes ,
No,
Minerals
not minerals
ICE
Petroleum – not a solid so no.
GOLD
Tree trunk – No, it was living so
no.
DIAMOND Orange Juice – not a solid so no
TALC
Seashells – No because they are
organic
QUARTZ
Granite – no because it is a rock
not a mineral.
Properties used to identify minerals
 Crystal structure
 Hardness
 Color
 Luster
 Specific Gravity (density)
 Streak
 Cleavage or fracture
 Special properties
*Inorganic = not organic – not made
by life processes.
*Composition = make up/formula
*Atom = tiny particles that make up
matter (composed of protons,
electrons, and neutrons)
 Every mineral has an orderly
arrangement of atoms and a
definite chemical composition
which gives it a unique set of
physical properties.
 The crystal form is the external
expression of a mineral’s orderly
arrangement of atoms.
There are 4,000 minerals on Earth.
Crystalline means that atoms are arranged in a
pattern that is repeated over and over again.
 Only a solid can be a mineral.
Ex. An Opal is not a mineral because it atoms are
 Not all solids are minerals.
not all arranged in a definite, repeating pattern (even
though it is a naturally occurring, inorganic solid).
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Crystal = a solid which the atoms are arranged in orderly, repeating patterns.
A crystal system is a group of crystals Crystals form by many processes.
that have similar atomic arrangements
and similar external crystal shapes.
Ex. 1 – crystals that form from magma
Ex. 2 – crystals that form from solutions of salts.
Ex. hexagonal, tetragonal, and cubic.
Example:
 Because the rose quartz crystals developed in a
The rose quartz has atoms arranged in
tight space.
repeating patterns but you can’t see the
crystal shape on the outside of the
mineral. Why? →
 The clear quartz crystals developed in freely in
an open space.
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Crystals from Magma
 Naturally processes form minerals in many ways as mentioned above.
When magma cools slowly then the crystals
Magma
Hot melted rock material which cools when it that form are usually large enough to see
reaches Earth’s surface or even when it is
with the eye.
trapped below the surface.→
 Why? Because atoms have enough
time to move together and form into
larger crystals.
When magma cools rapidly (quickly), the
crystals that form will be small and you can’t
easily see the individual mineral crystals.
Crystals from Solution
Crystals can form from When water evaporates, (as one might see
minerals dissolved in
in a dry climate like Nevada or
water
California) ions that are left behind can
come together to form crystals.
An example of this is the halite crystals
If too much of a
substance is dissolved
in water, ions can come
together and crystals of
that substance can
begin to form in the
solution.
 Minerals can form
from a solution in
this way without the
need for
evaporation.
Located in Death Valley, California
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Mineral Compositions and Groups
90 elements occur naturally in Earth’s crust.
Most of Earth’s crust is composed of 8
elements.
 Oxygen(most abundant/plentiful)
 Silicon (most abundant/plentiful)
 Aluminum
 Iron
 Calcium
 Sodium
 Potassium
 Magnesium
Most of the rock forming minerals belong to a Silicates = minerals that contain silicon and
group called the silicates.→
oxygen and usually one or more other
elements.
 Oxygen (O) and Silicon (Si) are 2
elements that form the basic building
blocks of most of minerals in Earth’s
crust and mantle.
Feldspar = silicate
Quartz = silicate
Calcite = carbonate
All of these are examples of rock-forming
minerals.
Feldspar
Quartz
Calcite
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