Rocks and MineralsRocks and Minerals

Ms. SandersonMs. Sanderson

What is the difference between What is the difference between a Rock and a Mineral?a Rock and a Mineral?

Minerals: Minerals: – Naturally occurringNaturally occurring– InorganicInorganic– SolidSolid– Definite chemical Definite chemical

structure (4000 structure (4000 known to man)known to man)

Rock: made up of Rock: made up of minerals minerals (aggregates (aggregates mixture)mixture)

MineralsMinerals

The The buildingbuilding blocks of blocks of mineralsminerals are are elementselements

ELEMENTSELEMENTSThe Building blocks for minerals.The Building blocks for minerals.Is a Is a substancesubstance that that cannotcannot be be

broken down into broken down into simplersimpler substances by substances by chemicalchemical or or physicalphysical meansmeans

Organized by their properties in the Organized by their properties in the Periodic TablePeriodic Table

PERIODIC TABLEPERIODIC TABLE

MOST COMMON MOST COMMON ELEMENTS ON CRUST OF ELEMENTS ON CRUST OF

EARTHEARTHOxygenOxygen46.6%46.6%SiliconSilicon 27.7 % 27.7 %Aluminum Aluminum 8.1 % 8.1 %IronIron 5% 5%CalciumCalciumSodiumSodiumPotassiumPotassiumMagnesiumMagnesium

ATOMSATOMSAre the Are the smallest smallest particle of particle of mattermatter that that

contains the characteristics of an contains the characteristics of an elementelement..

Parts of an Atom:Parts of an Atom:NucleusNucleus Central region of the atom.Central region of the atom.

– Contains Contains ProtonsProtons and and NeutronsNeutronsEnergy LevelsEnergy Levels area where electrons area where electrons

traveltravel

ProtonsProtons

Positively charged “+” subatomic Positively charged “+” subatomic particleparticle

Found in the nucleusFound in the nucleus The atomic number of the elementThe atomic number of the element

NeutronsNeutrons

Neutrally charged subatomic Neutrally charged subatomic particleparticle

Found in the nucleusFound in the nucleus Same mass as a protonSame mass as a proton

ElectronsElectrons

Smallest part of an atomSmallest part of an atom Negatively charged “—” subatomic Negatively charged “—” subatomic

particleparticle Found in the energy levels Found in the energy levels

surrounding the nucleussurrounding the nucleus Located in regions called Located in regions called Energy Energy

LevelsLevels which surround the nucleus which surround the nucleus

ISOTOPESISOTOPES

Atoms with the Atoms with the same number of same number of protons but protons but different number different number of neutronsof neutrons– Neutron Neutron

changechange

BONDSBONDS Compounds:Compounds: Is a substance that consists of two Is a substance that consists of two

or more elements that are chemically combined in or more elements that are chemically combined in specific proportions.specific proportions.

Chemical Bond:Chemical Bond: forces that hold atoms together forces that hold atoms together in a compoundin a compound

Three Types of BondsThree Types of Bonds– IonicIonic– CovalentCovalent– MetallicMetallic

Ionic and Covalent Ionic and Covalent BondsBonds

IonicIonic Atoms gain or lose Atoms gain or lose

electrons (transfer of electrons (transfer of electrons)electrons)

Between a metal and Between a metal and nonmetalnonmetal

EX: salts, calcium fluorideEX: salts, calcium fluoride

CovalentCovalent Form when atoms Form when atoms

share electrons.share electrons. Between Nonmetal Between Nonmetal

and Nonmetaland Nonmetal Ex: Water, diamondEx: Water, diamond

METALLIC BONDSMETALLIC BONDS Form when electrons are shared by metal ions.Form when electrons are shared by metal ions. Metals are malleable, ductile and conductors.Metals are malleable, ductile and conductors. Between Metal and MetalBetween Metal and Metal Sharing of electron pool give metals their Sharing of electron pool give metals their

propertiesproperties

How Minerals FormHow Minerals Form

Four WaysFour Ways– Crystallization from magmaCrystallization from magma– PrecipitationPrecipitation– Changes in Pressure and TemperatureChanges in Pressure and Temperature– Hydrothermal SolutionsHydrothermal Solutions

Crystallization from MagmaCrystallization from Magma

As magma cools, elements combine As magma cools, elements combine to form minerals.to form minerals.

Crystal structure depends on rate of Crystal structure depends on rate of cooling and pressurecooling and pressure

First to Crystallize:First to Crystallize: minerals rich minerals rich in iron, calcium and magnesiumin iron, calcium and magnesium

Precipitation Precipitation

Water evaporates, some dissolved Water evaporates, some dissolved substances can react to form substances can react to form mineralsminerals

When minerals are dissolved out of a liquid.When minerals are dissolved out of a liquid. Through evaporation or temperature change of Through evaporation or temperature change of

water. water. ExamplesExamples

– CalciteCalcite– HaliteHalite

Pressure and TemperaturePressure and Temperature

An increase of An increase of pressurepressure can cause a can cause a mineral to recrystallize while still mineral to recrystallize while still solidsolid

Changes in Changes in temperaturetemperature can also can also cause certain minerals to become cause certain minerals to become unstable and recrystallize to form a unstable and recrystallize to form a new mineral that is stable at the new new mineral that is stable at the new temperature.temperature.

Examples: talc and muscoviteExamples: talc and muscovite

Hydrothermal SolutionsHydrothermal Solutions

Very hot mixture of water and Very hot mixture of water and dissolved substancedissolved substance

When these solutions come into When these solutions come into contact with existing minerals, contact with existing minerals, chemical reactions take place to form chemical reactions take place to form new minerals.new minerals.

Examples:Examples:– QuartzQuartz– PyritePyrite

Mineral GroupsMineral Groups

Over 3800 minerals have been namedOver 3800 minerals have been named Minerals are classified into groups Minerals are classified into groups

based on their compositionbased on their composition– SilicatesSilicates– Sulfides & SulfatesSulfides & Sulfates– HalidesHalides– CarbonatesCarbonates– OxidesOxides– Native ElementsNative Elements

SilicatesSilicates

Most common group on EarthMost common group on Earth Silicon and Oxygen combine to form a Silicon and Oxygen combine to form a

structure called the silicon-oxygen structure called the silicon-oxygen tetrahedrontetrahedron

Two most abundant elements are Two most abundant elements are SILICON AND OXYGENSILICON AND OXYGEN

EX: QuartzEX: Quartz

AugiteAugite

MicasMicas

CarbonatesCarbonates

Second most common mineral Second most common mineral group.group.

Contains the element carbon, Contains the element carbon, oxygen and one or more other oxygen and one or more other metallic elementsmetallic elements

Ex: Ex: – CalciteCalcite– DolomiteDolomite

OxidesOxides

Minerals that Minerals that contain oxygen contain oxygen and one or more and one or more other elements, other elements, which are usually which are usually metalsmetals

Ex:Ex:– RutileRutile– CorundumCorundum– HematiteHematite

Sulfides & SulfatesSulfides & Sulfates

Contains the Contains the element sulfur & element sulfur & other elementsother elements

Ex:Ex:– GypsumGypsum– GalenaGalena– Pyrite Pyrite

HalidesHalides

Contains a halogen Contains a halogen ion plus one or ion plus one or more other more other elements.elements.

Elements from Elements from Group 7A on the Group 7A on the periodic table-- like periodic table-- like fluorine and fluorine and chlorine. chlorine.

Ex:Ex:– HaliteHalite– FluoriteFluorite

Native ElementsNative Elements

Group of minerals Group of minerals that exist in that exist in relatively pure relatively pure formform

Ex:Ex:– GoldGold– SilverSilver– CopperCopper– SulfurSulfur– CarbonCarbon

Properties of Minerals—used to Properties of Minerals—used to identify mineralsidentify minerals

StreakStreak ColorColor LusterLuster Crystal FormCrystal Form Hardness ScaleHardness Scale CleavageCleavage

FractureFracture DensityDensity TextureTexture MagneticMagnetic ConductorConductor Reaction with AcidReaction with Acid

ColorColor

Not a useful tool for identificationNot a useful tool for identification Small amount of different elements Small amount of different elements

can give the same mineral different can give the same mineral different colorscolors

Olivine = greenish tintOlivine = greenish tint

StreakStreak

The color of a mineral in its The color of a mineral in its powdered form.powdered form.

Found by rubbing mineral across a Found by rubbing mineral across a streak plate.streak plate.

Example: Galena (below) using an Example: Galena (below) using an unglazed porcelain tileunglazed porcelain tile

LusterLuster How light is reflected from the surface of a How light is reflected from the surface of a

mineral (how shiny it is)mineral (how shiny it is) Two types: Metallic: looks like a metal & Two types: Metallic: looks like a metal &

Nonmetallic: does not look like a metalNonmetallic: does not look like a metal

Crystal FormCrystal Form

Visible expression of Visible expression of minerals internal minerals internal arrangement of atomsarrangement of atoms

Structure of the mineralsStructure of the minerals Size depends on the length Size depends on the length

exposed to heat exposed to heat

HardnessHardness

A measure of the A measure of the resistance of a resistance of a mineral to being mineral to being scratchedscratched

Measured on Mohs Measured on Mohs Hardness scaleHardness scale

10 minerals 10 minerals arranged from 10 arranged from 10 (hardest) to 1 (hardest) to 1 (softest)(softest)

Finger NailFinger Nail2.52.5Copper pennyCopper penny

3.53.5GlassGlass 5.5 5.5Streak PlateStreak Plate

6.56.5

CleavageCleavage

Tendency of a mineral to break along Tendency of a mineral to break along flat even planes.flat even planes.

Micas show the simplest type of Micas show the simplest type of cleavage.cleavage.

FractureFracture

The uneven breakage of a mineralThe uneven breakage of a mineral If a mineral does not have cleavage If a mineral does not have cleavage

then it has fracturethen it has fracture

Density Density

The ratio of an objects mass to its volume.The ratio of an objects mass to its volume. Each mineral has its own unique densityEach mineral has its own unique density Density of Gold is 19.3 g/cm^3Density of Gold is 19.3 g/cm^3

Other:Other:

Texture (soapy, greasy)Texture (soapy, greasy) Magnetism (attraction to a magnet)Magnetism (attraction to a magnet) Smell (sulfur smells like a rotten egg)Smell (sulfur smells like a rotten egg) Reaction to acid (mineral fizzes)Reaction to acid (mineral fizzes)

Double RefractionsDouble Refractions– When a piece of transparent calcite is placed When a piece of transparent calcite is placed

over printed material, the letters appear over printed material, the letters appear doubled.doubled.

TextureTexture MagneticMagnetic

What does it feels What does it feels like.like.

Mica - brittle Mica - brittle Talc - soapyTalc - soapy

Attracted or Attracted or repelled by a repelled by a magnet.magnet.

Example: Example: MagnetiteMagnetite

ConductorConductor Rxn with Acid Rxn with Acid

Does it conduct Does it conduct electricity?electricity?

Does it fizz in acid?Does it fizz in acid? Mostly tested with Mostly tested with

HCL. Calcite below:HCL. Calcite below:

What is a ROCK?What is a ROCK?

Any solid mass of mineral or mineral-Any solid mass of mineral or mineral-like matter that occurs naturally as like matter that occurs naturally as part of our planetpart of our planet

Three types of rock:Three types of rock:

1.1. Igneous Igneous

2.2. SedimentarySedimentary

3.3. MetamorphicMetamorphic

The Rock CycleThe Rock Cycle

Interaction among Earths water, air, Interaction among Earths water, air, land, and living things can cause land, and living things can cause rocks to change from one type to rocks to change from one type to anotheranother

A continuous processA continuous process

Igneous RocksIgneous Rocks

Form when magma or lava hardensForm when magma or lava hardens

LAVA vs. MAGMALAVA vs. MAGMA

LavaLavaMolten rock Molten rock

on the on the surface of surface of EarthEarth

MagmaMagmaMolten rock Molten rock

beneath beneath Earth’s surfaceEarth’s surface

Formation of Igneous RocksFormation of Igneous Rocks

Intrusive Igneous Intrusive Igneous RocksRocks

Rocks that form Rocks that form when magma when magma hardens beneath hardens beneath Earth’s surfaceEarth’s surface

EX: GraniteEX: Granite

Extrusive Igneous Extrusive Igneous RocksRocks

Rocks that form Rocks that form when lava when lava hardens on the hardens on the surface of the surface of the Earth Earth

EX: RhyoliteEX: Rhyolite

Classification of Igneous RocksClassification of Igneous Rocks

Texture & composition are two Texture & composition are two characteristics used to classify characteristics used to classify igneous rocks.igneous rocks.

Classification of Igneous RocksClassification of Igneous Rocks

TextureTexture=size, =size, shape, and shape, and arrangement of arrangement of interlocking interlocking crystalscrystals

OBSIDIAN-EXTRUSIVE

TextureTexture

Coarse-GrainedCoarse-Grained Slow cooling Slow cooling Large crystalsLarge crystals

Fine-GrainedFine-Grained Rapid cooling of Rapid cooling of

magma or lavamagma or lava Small, Small,

interconnected interconnected mineral grains mineral grains

Peridotite

IntrustiveAndesite--extrusive

TextureTexture

GlassyGlassy Extrusive Igneous Extrusive Igneous

RockRock Looks like glassLooks like glass

PorphyriticPorphyritic Large crystals Large crystals

embedded in a embedded in a matrix of much matrix of much smaller crystalssmaller crystals

Porphyritic Andesite-extrusive

Obsidian--extrusive

CompositionComposition

CompositionComposition=Based on =Based on proportions of light and dark proportions of light and dark mineralsminerals

TypesTypes– GraniticGranitic– BasalticBasaltic– Andesitic Andesitic – UltramaficUltramafic

CompositionComposition

Basaltic Basaltic Contains many dark silicate minerals and Contains many dark silicate minerals and

plagioclase feldsparplagioclase feldspar Rich in magnesium & ironRich in magnesium & iron Example: basalt & gabbroExample: basalt & gabbro

CompositionComposition

GraniticGranitic Made almost entirely of light-colored Made almost entirely of light-colored

silicate minerals like quartz and silicate minerals like quartz and feldsparfeldspar

0 to 25% dark minerals0 to 25% dark minerals Example: biotite & amphiboleExample: biotite & amphibole

Other CompositionOther Composition

AndesiticAndesitic Between granitic and basalticBetween granitic and basaltic At least 25% dark mineralsAt least 25% dark minerals

CompositionComposition

UltramaficUltramafic Composed mainly of iron and Composed mainly of iron and

magnesium-rich mineralsmagnesium-rich minerals Almost entirely dark mineralsAlmost entirely dark minerals

Comp/Comp/

TextureTextureGranitGranitee

AndesiticAndesitic BasalticBasaltic UltramaficUltramafic

CoarseCoarse GraniteGranite DioriteDiorite GabbroGabbro PeriodtitePeriodtite

FineFine PhyolitePhyolite AndesiteAndesite BasaltBasalt KematiteKematite

PorphyriticPorphyritic Inside any given rockInside any given rock UncommonUncommon

GlassyGlassy Obsidian, PumiceObsidian, Pumice

What is a Sedimentary Rock?What is a Sedimentary Rock?

Forms when Forms when existing rocks are existing rocks are broken down into broken down into sediment then sediment then compacted and compacted and cemented togethercemented together

Formation of Sedimentary RockFormation of Sedimentary Rock

InvolvesInvolves

– WeatheringWeathering is the next step—any is the next step—any process that breaks rocks into sediment.process that breaks rocks into sediment.

– ErosionErosion– the removal of weathered – the removal of weathered rocksrocks

Formation of Sedimentary RocksFormation of Sedimentary Rocks

– DepositionDeposition-- When the agents of -- When the agents of erosion (wind, water, ice or gravity) erosion (wind, water, ice or gravity) loses energy, it drops the sediment.loses energy, it drops the sediment.

– CompactionCompaction—process that squeezes or —process that squeezes or compacts sediment togethercompacts sediment together

– CementationCementation takes place when takes place when dissolved minerals are deposited in the dissolved minerals are deposited in the tiny spaces among the sedimenttiny spaces among the sediment

Classification of Sedimentary RockClassification of Sedimentary Rock

Classified into two Classified into two main groups main groups according to the according to the way they form.way they form.– Either Clastic or Either Clastic or

ChemicalChemical

Rock Salt

Chemical

Clastic Sedimentary RockClastic Sedimentary Rock

Made of weathered Made of weathered bits of rocks & bits of rocks & mineralsminerals

Grouped according Grouped according to size of the to size of the sedimentssediments

Conglomerate

Clastic

Grain sizeGrain size Sediment Sediment NameName

Rock NameRock Name

Coarse (over Coarse (over 2mm in size)2mm in size)

Gravel-roundedGravel-rounded ConglomerateConglomerate

Gravel-angularGravel-angular BrecciaBreccia

Medium (2mm Medium (2mm to 1/6 mm)to 1/6 mm)

SandSand SandstoneSandstone

Fine (1/16 to Fine (1/16 to 1/256 mm)1/256 mm)

SiltSilt SiltstoneSiltstone

Very fine (less Very fine (less than 1/256 than 1/256 mm)mm)

MudMud Shale/mudstoneShale/mudstone

Chemical Sedimentary RockChemical Sedimentary Rock

Form when dissolved minerals Form when dissolved minerals precipitate from water solutionprecipitate from water solution(Rock salt and flint)(Rock salt and flint)

Biochemical Sedimentary RocksBiochemical Sedimentary Rocks– Made from once living organisms like Made from once living organisms like

shells and skeleton remainsshells and skeleton remains– Ex: Chalk, Limestone, rock saltEx: Chalk, Limestone, rock salt

CompositionComposition TextureTexture Rock NameRock Name

CalciteCalcite Fine to coarseFine to coarse

Visible shellsVisible shells

Small shells Small shells and clayand clay

LimestoneLimestone

CoquinaCoquina

ChalkChalk

QuartzQuartz Very fineVery fine Chert (light Chert (light colored)colored)

Flint (dark Flint (dark colored)colored)

GypsumGypsum Fine to coarseFine to coarse Rock GypsumRock Gypsum

HaliteHalite Fine to coarseFine to coarse Rock SaltRock Salt

Altered plant Altered plant fragmentsfragments

Fine-grained Fine-grained organic matterorganic matter

CoalCoal

What is a Metamorphic RockWhat is a Metamorphic Rock

Form when existing Form when existing rocks are changed rocks are changed by heat and by heat and pressurepressure

Metamorphism—Metamorphism—means “change means “change form”form”

Agents of MetamorphismAgents of Metamorphism

The agents of metamorphism areThe agents of metamorphism are– HeatHeat provides the energy provides the energy

needed to drive chemical needed to drive chemical reactions which causes existing reactions which causes existing minerals to recrystallize.minerals to recrystallize.

Agents of MetamorphismAgents of Metamorphism

– PressurePressure applied in all directions applied in all directions on a rock which causes spaces on a rock which causes spaces between grains to closebetween grains to close

– Hydrothermal solutionsHydrothermal solutions hot, hot, water solution that promote water solution that promote recrystallization by dissolving recrystallization by dissolving original minerals & then depositing original minerals & then depositing new onesnew ones

Classification of Metamorphic Classification of Metamorphic RocksRocks

Classified by Classified by texture & texture & compositioncomposition

– TextureTexture FoliatedFoliated Non-foliatedNon-foliated

– CompositionComposition

Greenstone

Non-foliated

Foliated Metamorphic RocksFoliated Metamorphic Rocks

A rock with layered or A rock with layered or banded appearance banded appearance that had been that had been metamorphosed metamorphosed

Example: GneissExample: Gneiss Four Main TypesFour Main Types

– SlateSlate– PhyllitePhyllite– SchistSchist– GneissGneiss

Gneiss

SlateSlate

PhyllitePhyllite

SchistSchist

GneissGneiss

Non-foliated Metamorphic Non-foliated Metamorphic RocksRocks

Does not have a Does not have a banded texturebanded texture

Contains only one Contains only one mineralmineral

Ex: MarbleEx: Marble– Calcite crystalsCalcite crystals

Quartzite—made from QuartzQuartzite—made from Quartz

Anthracite—made of CoalAnthracite—made of Coal

Rock Rock NameName

TextureTexture Grain Grain SizeSize

Parent Parent RockRock

SlateSlate foliatedfoliated Very fineVery fine Shale, Shale, mudstone, or mudstone, or

siltstonesiltstone

PhyllitePhyllite foliatedfoliated FineFine SlateSlate

SchistSchist foliatedfoliated Medium to Medium to coarsecoarse

PhyllitePhyllite

GneissGneiss foliatedfoliated Medium to Medium to coarsecoarse

Schist, phyllite, Schist, phyllite, or volcanic or volcanic

rocksrocks

MarbleMarble Non-Non-foliatedfoliated

Medium to Medium to coarsecoarse

Limestone, Limestone, dolostonedolostone

QuartziteQuartzite Non-Non-foliatedfoliated

Medium to Medium to coarsecoarse

Quartz Quartz sandstonesandstone

AnthraciteAnthracite Non-Non-foliatedfoliated

finefine CoalCoal