MINERALS

http://www.youtube.com/watch?v=TYvye0CVbU0

Matter

• anything that has mass and takes up space

• Matter is composed of elements

Element• A substance that cannot be broken down

into simpler substances by ordinary chemical means

Composition of Earth’s Crust

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A grouping of atoms - Molecule

Most common molecule in Earth’s crust • Silica Tetrahedron

Composed of …

1 silicon atom

4 oxygen atoms

Silica Structure

4 oxygen atoms for every 1 silicon atom

Olivine

Feldspar, Quartz

Micas

Amphibole (Hornblende)

Pyroxenes (Augite)

Complexity Temp.

MINERALS• Naturally occurring• Inorganic (never

alive)• Definite chemical

composition• Crystal structure

because of the internal arrangement of atoms

A mineral is the building block of rocks

Native Minerals– Made of single

elements• Gold (Au)• Copper (Cu)• Sulfur (S)

Compound Minerals– Made of two or

more elements• Silicate Family

– A compound of silicon and oxygen

– 90% of the Earth’s crust is composed of silicates

Examples:–

Quartz SiO2

–Olivine (Fe,Mg)2Sio4

Chemical formula:

CChemical formula:

C

Graphite Diamond

How can 2 minerals with the same composition be so different?

What’s the point here?

“Internal Arrangement of Atoms” controls most physical properties!

MINERAL PROPERTIES FOR IDENTIFICATION

a. Color

Least dependable property because some minerals have lots of different colors

b. Luster

Appearance of the mineral surface in reflected light, how the mineral shines

Metallic – looks like a metal Non-Metallic

c. Hardness

• Resistance to being scratched

• https://www.youtube.com/watch?v=b7ANcWQEUI8

Moh’s Hardness Scale

softest

hardest

d. Streak

• Powdered form of a mineral, more reliable than color

e. CleavageTendency of minerals to split along repeated

smooth, flat planes.

Look for places where the mineral might have split along flat and sometimes shiny planes that usually reflect light well.

Look for stairsteps, sheets, squares, cubes

e. FractureMineral breaks has a jagged or lumpy, irregular appearance

f. Crystal shape• Geometric pattern

that a lone crystal of the mineral will have

SPECIAL PROPERTIES

Fluorescence – mineral glows under a black light

Double refraction

Magnetism – some minerals are attracted to a magnet

Taste – DO NOT EVER TASTE A MINERAL

Reaction to acids

Calcite and Dolomite will bubble when Hydrochloric Acid

All mineral properties are determined by

• The internal arrangement of atoms

ROCK

Composed of one or more minerals

Classified by

1. Origin – how they were formed

2. Mineral Content

3. Texture

3 Types

• Igneous

• Sedimentary

• Metamorphic

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