Uploaded by Connor Fleming

Minerals and crystals (year 8 standard)

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Crystal Growth
How does the change in temperature affect
the sizes of and amount of crystals present?
Special crystal landmarks in Mexico:
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How to identify if something is a mineral?
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Key properties of classifying minerals.
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A Substance That Is:
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Naturally occurring
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Inorganic
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Solid
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Consistent Chemical Make-Up
(not created by any organisms)
(has a repeating
chemical pattern)
Naturally occurring means that
people did not make it. Steel is
not a mineral because it is an
alloy produced by people.
Inorganic means that the
substance is not made by an
organism. Wood and pearls are
made by organisms and thus
are not minerals.
Solid means that it is not a
liquid or a gas at standard
temperature and pressure.
Consistent Chemical Make-Up means that all
occurrences of that mineral have the same chemical
composition, and the atoms in the mineral are
arranged in a organized and repeating pattern.
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There are five main properties geologists use to
classify a mineral. These are:
Colour
Hardness
(the resistance to scratching)
Lustre
(the shine or reflection of light)
Cleavage
(the direction in which it breaks)
Density
(the mass per unit volume)
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Why is colour not the best way to determine
the identity of a mineral?
What is the hardest mineral in the world?
Using one of the five main properties, explain
why a bucket filled with gold may be heavier
than a bucket filled with quartz.
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Don’t get tricked
by this special
gold-coloured
mineral:
A lot of minerals have
the same colour as
each other, and colour
is easily changed by
dust/dirt or paints.
Moh’s Scale of Mineral Hardness
Non-linear scale Invented in 1812
Still relevant as a rough comparison tool
Density is how much matter is in the mineral.
 It is measured by the substance’s mass per
unit volume
 For minerals
you will see the
units g/cm3 or
g/cc which
means grams per
cubic centimetre.
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