Unit 9 Rocks and Minerals

Topic: Minerals  Key terms:  Matter  Elements  Atoms  Mineral

Mineral Uses Quartz

Graphite

Halite

Talc

Gypsum

How many different minerals are there?  4,000 known minerals, according to the International Mineralogical Association International Mineralogical Association International Mineralogical Association

Elements ---- ---- ----

Matter ----

Atoms mmmmade of three particles PPPProtons=Positive(+) NNNNeutrons=Neutral(0) EEEElectrons=Negative(-)

Take out ESRT pg 1

Atoms make up Elements… Elements make up MINERALS!!!

What is a mineral? 1)Solid 2)Inorganic: not, or never was, living

3) Definite chemical composition  Elements that make up the mineral  Example: Mineral Halite (aka Salt) Composition: Sodium (Na) & Chlorine (Cl) Chemical Formula: NaCl

4) Crystalline structure The pattern of molecules repeated throughout the mineral – gives a mineral it’s properties! gives a mineral it’s properties!

5) Naturally Occurring

Silicon Tetrahedron - -

Review: What is a mineral? ---- ---- ---- ---- ----

Final Question:  Can water, H 2 O, ever be considered a mineral? If so, how?

Topic: Identifying Minerals  Key Term:  Color  Streak  Hardness  Luster  Cleavage  Fracture

*-

Look at the last page of ESRT to find the minerals you need to know.

On the mineral chart Elements that make up the minerals

Tests for Identifying Minerals

Test 1: Color Test

*Color is not the best property to use when identifying a mineral. Why? 1) - 2) -

Test 2: Luster  Luster -

 Metallic - Non-metallic -

Luster Metallic dullglassypearly Non-Metallic All minerals

Luster Examples of Metallic Luster Pyrite, Galena

Luster Examples of Non- Metallic Luster (Dull) Earthy Corundum Glassy Quartz Pearly Opal

Find Hematite on mineral chart  What is unique about hematite’s luster? Either

Test 3: Streak Test  The streak - We use a streak plate

Where is streak on the chart? Look under Distinguishing characteristics to find streak

Pyrite is a brassy yellow, but in a powder is green-black

What is the color of hematite's streak?

Test 4: Hardness Test  A mineral’s hardness is -

Hardness Test  Mohs Scale of Hardness (1-10) 1.Talc6.Feldspar 2.Gypsum7.Quartz 3.Calcite8.Topaz 4.Fluorite9.Corundum 5.Apatite10.Diamond

Hardness Tools  Fingernail 2.5  Penny 3.5  Iron Nail4.5  Glass Plate5.5  Steel File6.5  Streak Plate7

Hardness Test Talc = hardness of 1 Diamond = hardness of 10

Test 5: The way a mineral breaks 1) Cleavage -

 Basal Cleavage: Mica

 Cubic Cleavage: Halite

 Rhombohedral Cleavage: Calcite

2) Fracture- - Rose Quartz

 Splintery Fracture: Hornblende

 Conchoidal Fracture: Obsidian

The check indicates if a mineral has fracture or cleavage

Watch out for Crystals Pyrite – looks like flat surfaces, however these crystals did not break, they grew into this shape.

Other identification tests

HCl Acid Calcite  Acid Test for Calcite and Dolomite  HCl— bubbles or fizzes

 Smell Test for Sulfur  Smells like rotten eggs

 Magnetism for Magnetite

 Taste Test for Halite

Optical Properties – Double refraction Mineral – Iceland Spar Calcite

Fluorescence: some minerals glow under ultraviolet light Franklinite from Franklin, New Jersey

Compare Diamond and Graphite Graphite Chemical Composition is Carbon (C) Diamond Can we use a diamond like we use graphite?

Arrangement of atoms