Minerals

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:

	Must occur naturally
	must be solid
	must have a definite chemical composition
	atoms must be arranged in an orderly pattern
	must be inorganic in origin (never alive)

Mineral Formation: – 3 Ways

	Cooling of hot melting material (magma) (crystal forming process)
	Evaporation - from minerals dissolved in solution (Halite - rock salt)
	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

	cubic (www.witn.psu.edu/articles/ images/crystal.jpg)
	Orthorhombic (www.gc.maricopa.edu/earthsci/ imagearchive/aragon1.jpg)
	Tetragonal (webmineral.com/specimens/ Marshite.jpg)
	Triclinic (www.aurora-schools.org/.../0001crystal%20lab/ triclinic.JPG)
	Hexagonal (emineralshow.com/images/ report11.jpg)
	Monoclinic (www.aurora-schools.org/.../0001crystal%20lab/ monoclinic.JPG)

Groups

Silicates – Si / O / other element

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

Other major groups are classified according to their composition

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

Identification

	Appearance –shape
	Hardness
	Determined by the Moh scale

Talc - softest / Diamond - hardest

Luster – how light is reflected

· Metallic or nonmetallic

	Color
	Streak

· Color when broken up and powered

Cleavage & Fracture

· Cleavage breaks along smooth lines

· Fracture breaks along rough jagged lines

	Other properties
	· Magnetic, chemical, refraction, …