Unit 3 – Minerals and Rocks Do Now – Number the pages (there should be 40) HW – You may clean out your folders

Minerals are: Important Vocabulary Today’s Objective: What is a Mineral? Naturally occurring – Forms by natural geologic processes. Solid substance

Inorganic – not living Calcite primarily comes from the remains of shells from living organisms Definite chemical composition – most are made up of two or more elements.

Orderly crystalline structure – atoms are arranged in an orderly and repetitive manner. Crystals – A solid body having a visually symmetrical pattern to it’s atomic arrangement

Example - Crystalline Structures Silicon and Oxygen combine to form a structure called the Silicon-Oxygen Tetrahedron. Sand (SiO 4 ) is a common silicate

Because the atoms are arranged differently. Diamond Graphite The following minerals are both made of pure Carbon, why do they look different?

How are minerals formed? Precipitates Minerals are left behind from a body of water when it evaporates Example - Rock Candy As the water evaporates the sugar is left behind

Heat and Pressure Changes minerals into new minerals Crystallize Minerals that form out of cooling magma

Hydrothermal Super heated water causes chemical reactions that change minerals into new ones.

A mineral’s properties are caused by its internal arrangement of atoms.

Color (NOT reliable) -Many minerals have the same color OR one mineral can have many colors -Small amounts of different elements can give the same mineral different colors. Properties of Minerals

Streak - Streak is the color of a mineral in its powdered form. - Streak is obtained by rubbing a mineral across a streak plate (a piece of porcelain.)

Hardness -Hardness is a measure of the resistance of a mineral to being scratched on glass. -The Mohs scale consists of 10 minerals arranged from 10 (hardest) to 1 (softest). - Glass has a hardness of about 5.5

Other - Few minerals bubble in the presence of an acid (Calcite and Dolomite)

Cleavage - Cleavage is the tendency of a mineral to cleave, or break, along flat, even surfaces. Fracture - Fracture is the uneven breakage of a mineral.

Luster - Luster is used to describe how light is reflected from the surface of a mineral. Metallic vs. Non-Metallic

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