Rocks and MineralsRocks and MineralsCh. 1 and 2Ch. 1 and 2

Grouping mineralsGrouping minerals

►How can you group the minerals your How can you group the minerals your group has been given?group has been given?

►Think of how you group other things in Think of how you group other things in nature:nature: CloudsClouds TreesTrees BirdsBirds BuildingsBuildings

What is a mineral?What is a mineral?

►A naturally occurring A naturally occurring ► inorganicinorganic► solid solid ►with a definite (but not fixed) chemical with a definite (but not fixed) chemical

compositioncomposition►and a highly ordered arrangementand a highly ordered arrangement

Minerals are made from elements

Most common elements:

Oxygen

Silicon

Aluminum

Iron

Calcium

Magnesium

Sodium

Potassium

Percentage by Weight

Properties of MineralsProperties of Minerals

1.1. Crystal formCrystal form

2.2. HabitHabit

3.3. CleavageCleavage

4.4. HardnessHardness

5.5. LusterLuster

6.6. ColorColor

7.7. StreakStreak

8.8. DensityDensity

Did you use any of these properties for grouping your minerals?

Crystal Form-Internal arrangement of atoms determines outward appearance

Habit-shape of a mineral or group of minerals

Geode Stalactitic Botryoidal

FibrousMammillary Radiating

Habit

Cleavage-preferred plane of weakness

Do all minerals have cleavage?

Mohs Hardness Scale

1 2

45

3

109

876

Mohs Hardness Scale

1 - Talc

2 - Gypsum

3 - Calcite

4 - Fluorite

5 - Apatite

6 - Potassium Feldspar

7 - Quartz

8 - Topaz

9 - Corundum

10 -Diamond

softest

hardest

fingernailCopper penny

glass

Streak plate

Vitreous - glass like

Resinous - resin like

Pearly - pearl like

Greasy - slippery

Luster-how a mineral reflects light

Non Metallic

Metallic - metal like

LusterMetallic Nonmetallic

Color-what is the usefulness of this attribute in identifying minerals?

Color of Streak

box of feathers

box of hammers

Density

Important crustal minerals

Feldspar group (plagioclase and orthoclase)

Quartz

Calcite and dolomite

Pyroxene group

Amphibole group (biotite and muscovite)

Olivine

Halite (salt)

gypsum

What is a rock?What is a rock?

►An aggregate of one or more mineralsAn aggregate of one or more minerals

Groups of rocksGroups of rocks► Igneous►Sedimentary►Metamorphic►Characterized by

how they form►Related by the rock

cycle

Rock CycleRock Cycle

Igneous rocksIgneous rocks

►Crystallize from a molten rock: magmaCrystallize from a molten rock: magma►Magma: liquid rock Magma: liquid rock beneathbeneath earth’s earth’s

surfacesurface►Lava: liquid rock Lava: liquid rock aboveabove earth’s surface earth’s surface► Igneous rocks classified on Igneous rocks classified on

Mineral sizeMineral size compositioncomposition

Igneous rocksIgneous rocks

► Intrusive igneous rocksIntrusive igneous rocks Cool below ground (slowly)Cool below ground (slowly) All minerals visible w/out microscopeAll minerals visible w/out microscope

►Extrusive igneous rocksExtrusive igneous rocks Cool above ground (fast)Cool above ground (fast) Most minerals too small to see w/out Most minerals too small to see w/out

microscopemicroscope

Igneous rocksIgneous rocks

► Intrusive igneous rocksIntrusive igneous rocks►Extrusive igneous rocksExtrusive igneous rocks

Intrusive or extrusive?Intrusive or extrusive?

Slow or fast cooling?Slow or fast cooling?

Intrusive or extrusive?Intrusive or extrusive?

Slow or fast cooling?Slow or fast cooling?

Light colored igneous rocksLight colored igneous rocks

►Granite and rhyoliteGranite and rhyolite

Intermediate igneous rocksIntermediate igneous rocks

► AndesiteAndesite

Dark colored igneous rocksDark colored igneous rocks

►Gabbro and basaltGabbro and basalt

Rock CycleRock Cycle► Igneous rocks can become what other kind of rocks?Igneous rocks can become what other kind of rocks?

Sedimentary rocksSedimentary rocks

►ClasticClastic sed rock: made of solid sed rock: made of solid particles once part of other rocksparticles once part of other rocks Classified by grain sizeClassified by grain size

►ChemicalChemical sed rock: made from sed rock: made from dissolved material in waterdissolved material in water Classified by chemical compositionClassified by chemical composition

►BiochemicalBiochemical sed rock: made of dead sed rock: made of dead plants and animalsplants and animals

Biochemical, chemical, or Biochemical, chemical, or detrital?detrital?

ClasticClastic sed rocks sed rocks►Big particlesBig particles Conglomerate Conglomerate►Sand size SandstoneSand size Sandstone►Small particles Mudstone (shale)Small particles Mudstone (shale)

Clastic sed rocksClastic sed rocks

►ConglomerateConglomerate►Clue: Clue:

Particles of Particles of lots of lots of different sizesdifferent sizes

Clastic sed rocksClastic sed rocks

►SandstoneSandstone►Clue: feels Clue: feels

sandysandy

Clastic sed rocksClastic sed rocks

►Mudstone Mudstone (shale)(shale)

►Clue: Clue: very small very small

particlesparticles No grit when No grit when

you taste ityou taste it

Chemical sed rocksChemical sed rocks

►LimestoneLimestone Made of calciteMade of calcite Clues: Clues:

►fizzes with acid fizzes with acid

►Often contains Often contains fossilsfossils

Chemical sed rocksChemical sed rocks

►Rock salt/haliteRock salt/halite Clue: tastes Clue: tastes

saltysalty►GypsumGypsum

Clue: easily Clue: easily scratched, not scratched, not saltysalty

Biochemical sed rocksBiochemical sed rocks

► Category of Category of chemical sed rockschemical sed rocks

► CoalCoal► Limestone if with Limestone if with

fossilsfossils

Importance of sed rocksImportance of sed rocks

►Key to interpreting Earth’s historyKey to interpreting Earth’s history