How to Identify a Mineral

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How to Identify a Mineral
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Mineral Identification

• We identify minerals so we can recognize valuable
  resources (useful or beautiful).

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Mineral Identification

• There are 7 tests performed on minerals so they
  can be identified.

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Test 1
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Test 1

• Mineral Appearance Color and appearance are two
  clues used to identify minerals.

Azurite can always be identified by its striking
blue color.
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Test 1

• However, this test is not enough to identify most
  minerals.

Which one is gold and which one is iron pyrite
(fools gold)?
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Test 2
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Test 2

• Hardness the measure of how easily a mineral can
  be scratched.

Talc can be scratched by a fingernail, diamonds
cannot be scratched by anything but another
diamond.
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http//www.cnn.com/2012/08/09/living/olympians-bit
e-medals/index.html
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Test 2

• Hardness is measured using a Mohs scale.

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Test 3
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Test 3

• Luster the way a mineral reflects light.

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Test 3

• A mineral can be metallic or non-metallic, such
  as glassy, dull, pearly, or silky.

Non-metallic, dull
Metallic
Non-metallic, glassy
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Test 4
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Test 4

• Specific Gravity a minerals weight is compared
  to the weight of an equal sized amount (volume)
  of water.

Gold has a specific gravity of 19, iron pyrite is
5 ( 5 times heavier than water.)
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Fake or real???
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Test 5
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Test 5

• Streak the color a mineral leaves on a porcelain
  tile.

Hematite (on left) looks gray, but leaves a
reddish-brown streak. Iron pyrite (on right) is
gold colored, but leaves a greenish-black streak.

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Test 6
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Test 6

• Cleavage or Fracture how a mineral breaks.

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Test 6

• Cleavage the physical property of some minerals
  that allows them to break along smooth, flat
  surfaces.

Mica always cleaves in thin, flat sheets. Halite
cleaves at 90 degree angles.
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Test 6

• Fracture the physical property of some minerals
  that causes them to break with uneven, rough, or
  jagged surfaces.

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Test 7
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Test 7

• Other properties some minerals have unique
  properties that allow them to be easily
  identified.

Magnetite will pick up iron like a magnet
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Test 7
Calcite can cause double images
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Test 7
Willemite and Calcite have a property known as
fluorescence, they will glow under uv light
These minerals glow in the mining tunnel when
under uv light
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Summary

• There are 7 tests to determine the identity of a
  mineral
• Color and appearance
• Hardness
• Luster
• Specific Gravity
• Streak
• Cleavage and Fracture
• Other Properties

http//www.youtube.com/watch?vc7wJP_K_sAQfeature
related
http//abcnews.go.com/US/oklahoma-teenager-finds-3
85-carat-canary-diamond/story?id20633996
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Review

1. What are the 7 tests?

Color and appearance Hardness Luster Specific
Gravity Streak Cleavage and Fracture Other
Properties
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Review

• Why do we sometimes need to do more than one
  test?
• It may be difficult to identify a mineral based
  on only one characteristic. It may share common
  features with other minerals.

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Review

• Which test uses the Mohs scale?
• Hardness

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Review

• What type of luster do each of the following
  minerals have? (Metallic or Non-metallic)
• Metallic, non-metallic, non-metallic, metallic

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Review

• What type of breakage do these minerals show?
• Cleavage, fracture, fracture

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Review

• 6. Which test is being performed here?
• Streak Test