Minerals:

Objectives:

    1.    List five characteristics all minerals share.

    2.    Give examples of two ways that minerals form.

    3.    List the physical properties used to identify minerals.

    4.    Describe how physical properties such as hardness and streak are used to identify minerals.

Resources:

 

Notes:

Minerals:  

Minerals are found on and below the Earth's crust.  There are about 4000 known minerals each having there own characteristics.  Most rocks are made of mineral compounds though all solid materials are not (coal is not a mineral)  No matter what the mineral, the following characteristics must be met to be considered a mineral:

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Must occur naturally

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must be solid

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must have a definite chemical composition

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atoms must be arranged in an orderly pattern

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must be inorganic in origin (never alive)

 

Mineral Formation: – 3 Ways

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Cooling of hot melting material (magma) (crystal forming process)

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 Evaporation - from minerals dissolved in solution (Halite - rock salt)

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 Precipitation - from minerals dissolved in solution

 

·        Crystal Shape

        Although there are around 4000 known minerals there crystals only make 6 basic shapes.  Since all minerals have repeating patterns of elements, all minerals form some type of crystals

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  cubic        (www.witn.psu.edu/articles/ images/crystal.jpg)

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Orthorhombic    aragon1.jpg (253225 bytes)(www.gc.maricopa.edu/earthsci/ imagearchive/aragon1.jpg)

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Tetragonal        (webmineral.com/specimens/ Marshite.jpg)

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Triclinic        (www.aurora-schools.org/.../0001crystal%20lab/ triclinic.JPG)

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Hexagonal    report11.jpg (28980 bytes)(emineralshow.com/images/ report11.jpg)

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Monoclinic    (www.aurora-schools.org/.../0001crystal%20lab/ monoclinic.JPG)

 

 

Groups

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Silicates – Si / O / other element

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Made of the two most abundant elements on earth's crust

 

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Other major groups are classified according to their composition

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Carbonates, oxides, sulfides, sulfates, halides, hydroxides, phosphates & native elements.

Identification

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Appearance –shape

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Hardness

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Determined by the Moh scale  

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 Talc - softest / Diamond - hardest      

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Luster – how light is reflected

·  Metallic or nonmetallic

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Color

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Streak

·  Color when broken up and powered

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Cleavage & Fracture

·  Cleavage breaks along smooth lines

·  Fracture breaks along rough jagged lines

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Other properties

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·  Magnetic, chemical, refraction, …

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