How to identify a mineral

Mineral Identification• We identify minerals so we can recognize valuable resources useful or beautiful... Mineral Identification• There are 7 tests performed on minerals so they can be

How to Identify a Mineral

Mineral Identification

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

Mineral Identification

• There are 7 tests performed on minerals

so they can be identified

Test 1

Test 1

• Mineral Appearance: Color and

appearance are two clues used to identify minerals

Azurite can always

be identified by its striking blue color.

Test 1

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

Test 2

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.

http://www.cnn.com/2012/08/09/living/olympians-bite-medals/index.html

Test 2

• Hardness is measured using a Mohs scale

Test 3

Test 3

• Luster: the way a mineral reflects light

Test 4

Test 4

• Specific Gravity: a mineral’s 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.)

Fake or real???

Test 5

Test 5

• Streak: the color a mineral leaves on a

porcelain tile

Test 6

Test 6

• Cleavage or Fracture: how a mineral breaks

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.

Test 6

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

Test 7

Test 7

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

Magnetite will pick up iron like a magnet

Test 7

Calcite can

cause double images

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

1 What are the 7 tests?

Color and appearanceHardness

LusterSpecific GravityStreak

Cleavage and FractureOther Properties

2 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.

3 Which test uses the Mohs scale?

Hardness

4 What type of luster do each of the

following minerals have? (Metallic or

Non-metallic)

Metallic, non-metallic, non-metallic, metallic

6 Which test is being performed here?

Streak Test