What Are Minerals?What Are Minerals?

Minerals – a Minerals – a naturally naturally occurring, occurring, inorganicinorganic solid solid that has a that has a crystalcrystal structure and a structure and a definite definite chemicalchemical compositioncomposition

What 5 Characteristics What 5 Characteristics Does a Mineral Have to Does a Mineral Have to

Have?Have?A mineral must be:A mineral must be: Naturally OccurringNaturally Occurring InorganicInorganic SolidSolid Crystal StructureCrystal Structure Definite Chemical Definite Chemical

CompositionComposition

What Does It Mean to Be What Does It Mean to Be Naturally Occurring?Naturally Occurring?

A mineral must occurA mineral must occur naturallynaturally

Cement, brick, steel, Cement, brick, steel, and glass all come from and glass all come from substances found in substances found in Earth’s Earth’s crustcrust but they but they are are manufacturedmanufactured by peopleby people

How Can Something Be How Can Something Be Inorganic?Inorganic?

InorganicInorganic – the mineral – the mineral cannotcannot arise from arise from materials that were materials that were once part of a once part of a livingliving thingthing

Ex. Ex. CoalCoal is is NOTNOT a a mineral because it is mineral because it is made up the made up the remainsremains of plants and animalsof plants and animals

What kind of pattern What kind of pattern must a mineral have?must a mineral have?

A mineral must have a A mineral must have a crystalcrystal structure – a structure – a repeatingrepeating pattern of a pattern of a mineral’s particles that mineral’s particles that forms a forms a solidsolid. .

FacesFaces – a crystal’s – a crystal’s flatflat side that meets at side that meets at sharpsharp edges and edges and cornerscorners

What kind of What kind of composition must a composition must a

mineral have?mineral have?A mineral must have A mineral must have a definite a definite chemicalchemical composition – it composition – it always contains always contains certain certain elementselements in in definite proportions; definite proportions; most minerals are most minerals are compoundscompounds

Cinnabar – composed of the

elements Mercury and

Sulfur

What Is the Difference Between What Is the Difference Between an Element and a Compound?an Element and a Compound?

Element – a substance Element – a substance composed of acomposed of a singlesingle kind ofkind of atomatom. . Ex. HydrogenEx. Hydrogen

Compound –Compound – TwoTwo or moreor more elementselements combinedcombined so that so that the elements no longer have the elements no longer have distinctdistinct propertiesproperties Ex. Ex. Water HWater H2200

All minerals can be divided into

SilicatesSilicates and Non-Non-silicatessilicates

•Silicates= SiSi and OO are the two most abundant elements in the earth’s crustearth’s crust.

What are the 2 groups of What are the 2 groups of minerals?minerals?

SiO4: One Silicon, Four

Oxygen

4% 4% of the Earth’s Crustof the Earth’s Crust

CarbonatesCarbonates, , HalidesHalides, , native elementsnative elements..

What are the Non-Silicates?What are the Non-Silicates?

Slide 10 cont’d more non-silicates

OxidesOxides>>>

sulfatessulfates>>

sulfidessulfides>>

How Do You Identify How Do You Identify Minerals?Minerals?

Properties:Properties:DensityDensityCrystal Crystal ShapeShape

Cleavage and Cleavage and FractureFracture

Special Special PropertiesProperties

HardnessHardnessColor (this Color (this can vary)can vary)

StreakStreakLusterLuster

How Do You Determine a How Do You Determine a Mineral’s Hardness?Mineral’s Hardness?

Friedrich Mohs invented a Friedrich Mohs invented a test to describe and test to describe and compare the compare the hardnesshardness of of mineralsminerals

Mohs Hardness ScaleMohs Hardness ScaleRanks Ranks tenten minerals from minerals from softestsoftest to to hardesthardest

How Does the Mohs Scale How Does the Mohs Scale Work?Work?

Gypsum (2) will Gypsum (2) will scratchscratch talc (1), talc (1), calcite (3) will calcite (3) will scratchscratch gypsum gypsum (2), fluorite (4) (2), fluorite (4) will scratch will scratch calcite (3), etc.calcite (3), etc.

TThe he GGeologist eologist CCan an FFind ind

AAn n OOrdinary rdinary QQuartz, uartz,

(that) (that) TTouristsourists CCall all

DDiamond!iamond!

To remember the Mohs scale To remember the Mohs scale try remembering this try remembering this

phrase:phrase:

What Is a Streak Test?What Is a Streak Test? The streak of a The streak of a mineralmineral is the is the colorcolor of its of its powderpowder

The streak color and The streak color and the mineral color are the mineral color are often often differentdifferent

To test: rub a mineral To test: rub a mineral against an unglazed against an unglazed tiletile ( (streakstreak plate) plate)

What is the Luster of a What is the Luster of a mineral?mineral?

Luster – used to describe Luster – used to describe how a mineralhow a mineral reflectsreflects lightlight from itsfrom its surfacesurface

Minerals containing Minerals containing metals are oftenmetals are often shinyshiny

EarthyEarthy, waxy, and , waxy, and pearlypearly

What does Density have to What does Density have to do with Minerals?do with Minerals?

Each mineral has a Each mineral has a characteristiccharacteristic DensityDensity

Density – or mass per unit Density – or mass per unit volume; Density = volume; Density = mass/volumemass/volume

Displacement – the Displacement – the volumevolume of of the the displaceddisplaced water equals the water equals the volume of the the samplevolume of the the sample

What Kind of Shape does What Kind of Shape does a Mineral have?a Mineral have?

Minerals have a crystal structureMinerals have a crystal structureCubicCubicHexagonalHexagonalTetragonalTetragonalOrthorhombicOrthorhombicMonoclinicMonoclinicTriclinicTriclinic

What is Mineral What is Mineral Cleavage?Cleavage? Cleavage – A Cleavage – A

mineral’s ability to mineral’s ability to splitsplit easily along a easily along a flatflat surface surface

The ability to The ability to breakbreak apart apart depends on the depends on the arrangement of the arrangement of the atomsatoms in the in the mineralmineral

Cubic Cleavage

Basal Cleavage

What is Mineral What is Mineral Fracture?Fracture?

Fracture – How a mineral Fracture – How a mineral lookslooks when it breaks when it breaks apartapart in an irregular way in an irregular way

What Special Properties What Special Properties does a Mineral have?does a Mineral have?

Fluorescence –minerals that Fluorescence –minerals that glowglow under ultraviolet light under ultraviolet light

Magnetism - ex. LoadstoneMagnetism - ex. Loadstone Chemical Reactivity- ex. Calcite Chemical Reactivity- ex. Calcite

gives off gives off carboncarbon dioxidedioxide ElectricalElectrical Properties – ex. Properties – ex.

quartzquartz

How are Minerals Formed?How are Minerals Formed? Two General Ways:

Crystallization of melted materialsMinerals from Magma

Crystallization of materials dissolved in waterMinerals from Hot water solutions

Minerals formed by evaporation

What is Crystallization?What is Crystallization?

Crystallization Crystallization the the processprocess by which by which atoms are atoms are arrangedarranged to to form a material with a form a material with a crystalcrystal structure structure

How do Minerals form from How do Minerals form from Magma?Magma?

Minerals form as Minerals form as magmamagma cools inside the cools inside the crustcrust, or , or as as lavalava hardens on the hardens on the surfacesurface

What Effects Crystal What Effects Crystal Size?Size?RateRate at which magma at which magma

coolscoolsSlower Slower coolingcooling forms forms larger crystalslarger crystals

The amount of The amount of gasgas the the magma containsmagma contains

The The chemicalchemical composition composition of the magmaof the magma

How do Minerals Form from How do Minerals Form from Hot Water Solutions?Hot Water Solutions?

MagmaMagma beneath Earth’s beneath Earth’s surface has heated the water surface has heated the water to a high temperature to a high temperature beneath Earth’s surface beneath Earth’s surface causing minerals to causing minerals to dissolvedissolve

When this solution When this solution coolscools the the elementselements and compounds and compounds leave the solution and leave the solution and crystallizecrystallize as minerals as minerals

How are Minerals Formed How are Minerals Formed by Evaporation?by Evaporation?

As water turns to As water turns to vaporvapor it it leaves behind the leaves behind the mineralmineral

Example: A salt water Example: A salt water solution leaves behind solution leaves behind large crystals of large crystals of saltsalt

Where are Minerals Where are Minerals Found?Found?

Earth’s crust is made up of a Earth’s crust is made up of a variety of minerals however; variety of minerals however; rarerare and less common minerals are and less common minerals are usually located near usually located near plateplate boundariesboundaries because of because of volcanicvolcanic activity and mountain buildingactivity and mountain building

How are Minerals Used?How are Minerals Used?

Minerals are the source ofMinerals are the source ofMetalsMetals ex. Aluminum, ex. Aluminum, IronIron

GemstonesGemstones ex. Rubies ex. Rubies and Sapphiresand Sapphires

Other Useful materials ex. Other Useful materials ex. TalcTalc (talcum powder) (talcum powder)

Ore What?Ore What?

Ore - A Ore - A rockrock that contains a that contains a metalmetal or economically or economically useful mineraluseful mineral

Most metals, gemstones, Most metals, gemstones, and useful minerals must be and useful minerals must be separatedseparated from their ores from their ores