MineralsMinerals

What is a Mineral?What is a Mineral? Naturally OccurringNaturally Occurring

InorganicInorganic SolidSolid Definite Chemical FormulaDefinite Chemical Formula

Definite Crystal StructureDefinite Crystal Structure

Naturally OccurringNaturally Occurring

Formed by natural processes not in Formed by natural processes not in the laboratory.the laboratory. Is an ice cube a mineral?Is an ice cube a mineral?

Is the ice on the windshield of a car a mineral?Is the ice on the windshield of a car a mineral?

Minerals manufactured by humans are Minerals manufactured by humans are not considered minerals.not considered minerals.

InorganicInorganic

Formed by inorganic processes; not livingFormed by inorganic processes; not living

Minerals are not made from living things.Minerals are not made from living things.

Coal is made of carbon. Is it a mineral?Coal is made of carbon. Is it a mineral?

SolidSolid

Minerals cannot be a gas or a liquid.Minerals cannot be a gas or a liquid.

- H- H22O as ice in a glacier is a mineral, but O as ice in a glacier is a mineral, but

water is not.water is not.

Definite Crystal StructureDefinite Crystal Structure Highly ordered atomic arrangement of Highly ordered atomic arrangement of

atoms in regular geometric patterns atoms in regular geometric patterns

Apatite

Feldspar

Diamond

Quartz

Minerals are crystals with a repeated Minerals are crystals with a repeated inner structure.inner structure.

Definite Chemical FormulaDefinite Chemical Formula Minerals are Minerals are

expressed by a expressed by a specific chemical specific chemical formula.formula.

- Gold (Au)Gold (Au)- Calcite (CaCOCalcite (CaCO33))

- Quartz (SiOQuartz (SiO22))- Pyrite (FeSPyrite (FeS22))

Minerals made of Minerals made of only one type of atom only one type of atom (element) are called (element) are called native elements.native elements.

GoldGold

CopperCopper

SilverSilver

Types of mineralsTypes of minerals Minerals are most commonly Minerals are most commonly

classified by chemical composition. classified by chemical composition. The 2 main groups are silicates and nonsilicates.The 2 main groups are silicates and nonsilicates.

SilicatesSilicates Minerals containing a combination of Minerals containing a combination of

silicon (Si) and oxygen (O) (most common silicon (Si) and oxygen (O) (most common elements in the earth’s crust)elements in the earth’s crust)

Silicate minerals comprise about 90% of the Earth’s Silicate minerals comprise about 90% of the Earth’s crust.crust.

Silicates minerals often contain other Silicates minerals often contain other elements such as aluminum, iron, elements such as aluminum, iron, magnesium, and potassium.magnesium, and potassium.

Granite is a rock comprised of the minerals Granite is a rock comprised of the minerals feldspar, biotite mica and quartz.feldspar, biotite mica and quartz.

FeldsparFeldspar Feldspar minerals make up Feldspar minerals make up

half of the Earth’s crust half of the Earth’s crust and is the main component and is the main component of most of the rocks found of most of the rocks found on the Earth’s surface.on the Earth’s surface.

FeldsparFeldspar

Feldspar contains Si, O, Feldspar contains Si, O, Al, K, Na, and CaAl, K, Na, and Ca

Biotite MicaBiotite Mica

Soft and shiny Soft and shiny minerals that minerals that separate easily into separate easily into sheetssheets

Biotite is one Biotite is one variety of mica variety of mica

QuartzQuartz

Silicon dioxide Silicon dioxide ( SiO( SiO22) is the basic ) is the basic

building block of building block of many rocksmany rocks

NonsilicatesNonsilicates

Minerals that do not contain the Minerals that do not contain the combination of Si and Ocombination of Si and O

Some of these minerals are made up Some of these minerals are made up of C, O, F, and Sof C, O, F, and S

Classes of NonsilicatesClasses of Nonsilicates Native ElementsNative Elements CarbonatesCarbonates HalidesHalides OxidesOxides SulfatesSulfates SulfidesSulfides

Native Native ElementsElements

Native elements Native elements are composed of are composed of only 1 elementonly 1 element

About 20 exist About 20 exist including Au, Pt, C, including Au, Pt, C, Cu, S and AgCu, S and Ag

CarbonatesCarbonates Contain the Contain the

combinations of combinations of carbon and Oxygen carbon and Oxygen in their chemical in their chemical structurestructure Calcite (CaCOCalcite (CaCO3 3 ) is an ) is an

exampleexample Carbonates are used Carbonates are used

in cement, building in cement, building stones and fireworksstones and fireworks

HalidesHalides Form when atoms containing Form when atoms containing

fluorine, chlorine, iodine, or fluorine, chlorine, iodine, or bromine (halogens) combine bromine (halogens) combine with potassium or calciumwith potassium or calcium

Fluorite

Halite (NaCl) is better Halite (NaCl) is better known as rock saltknown as rock salt

Fluorite can have many Fluorite can have many different colorsdifferent colors

Halides are often used in Halides are often used in making fertilizersmaking fertilizers

OxidesOxides Compounds formed Compounds formed

when elements like when elements like aluminum or iron aluminum or iron bond with oxygenbond with oxygen

Corundum (AlCorundum (Al22OO33) and ) and

Magnetite (FeMagnetite (Fe33OO44) are ) are

important oxidesimportant oxides Are used in abrasives Are used in abrasives

and airplane partsand airplane parts

SulfatesSulfates Minerals containing Minerals containing

sulfur and oxygen (SOsulfur and oxygen (SO44))

Gypsum

Gypsum (CaSOGypsum (CaSO4 4 * 2H* 2H22O) is a O) is a

common examplecommon example makes the white sand at makes the white sand at

White Sands National White Sands National Monument in NMMonument in NM

Sulfates are commonly Sulfates are commonly used in cosmetics, used in cosmetics, toothpaste and paintstoothpaste and paints

SulfidesSulfides Minerals containing Minerals containing

one or more elements one or more elements such as lead, iron, or such as lead, iron, or nickel combines with nickel combines with sulfursulfur

Galena

Galena (PbS) is a Galena (PbS) is a sulfidesulfide

Sulfides are used to Sulfides are used to make batteries, make batteries, medicines and medicines and electronic partselectronic parts

Composition of the Earth’s Composition of the Earth’s CrustCrust

- Oxygen (O)- Oxygen (O)- Silicon (Si)- Silicon (Si)- Aluminum (Al)- Aluminum (Al)- Iron (Fe)- Iron (Fe)- Calcium (Ca)- Calcium (Ca)- Sodium (Na)- Sodium (Na)- Potassium (K)- Potassium (K)- Magnesium - Magnesium (Mg)(Mg)

Eight Elements that make up over Eight Elements that make up over 98% of Earth’s Crust98% of Earth’s Crust

Where Do Minerals Come Where Do Minerals Come From?From?

Magma

Evaporation

In general, minerals form in two ways:Cooling magma - Crystallization of melted

materialsFrom solution - Crystallization of materials dissolved in water

a. At the surface

b. Beneath the surface

MagmaMagma Magma is molten material from the Magma is molten material from the

mantle that hardens to form rock.mantle that hardens to form rock. Lava is magma that reaches the surface.Lava is magma that reaches the surface.

Minerals form as hot magma cools Minerals form as hot magma cools inside the crust, or as lava hardens inside the crust, or as lava hardens on the surface.on the surface.

When these liquids cool to the solid When these liquids cool to the solid state, they form crystals.state, they form crystals.

Size of CrystalsSize of Crystals

Magma closer to the surface cools much Magma closer to the surface cools much faster, producing smaller crystals.faster, producing smaller crystals.

Slow cooling leads to the formation Slow cooling leads to the formation of large crystals.of large crystals.

When magma remains deep below When magma remains deep below the surface, it cools slowly over the surface, it cools slowly over many thousands of years.many thousands of years.

The chemical composition of the magmaThe chemical composition of the magma

The amount of gas the magma containsThe amount of gas the magma contains

The rate at which the magma coolsThe rate at which the magma cools

Depends of several factors:Depends of several factors:

Minerals from Hot Water Minerals from Hot Water SolutionsSolutions

This can happen on This can happen on the ocean floor the ocean floor when ocean water when ocean water seeps down through seeps down through cracks in the crust.cracks in the crust.

When a hot water solution begins to cool, When a hot water solution begins to cool, the elements and compounds leave the the elements and compounds leave the solution and crystallize as minerals.solution and crystallize as minerals.

A solution is a mixture in which one A solution is a mixture in which one substance dissolves in another.substance dissolves in another.

Sometimes, the elements that form a mineral Sometimes, the elements that form a mineral dissolve in hot water and form a solution.dissolve in hot water and form a solution.

Minerals formed by Minerals formed by EvaporationEvaporation

GypsumGypsum Calcite crystalsCalcite crystals Minerals containing potassiumMinerals containing potassium

Several other useful minerals also Several other useful minerals also from by the evaporation of seawater:from by the evaporation of seawater:

Minerals can also form when solutions Minerals can also form when solutions evaporate. Example: salt from sea waterevaporate. Example: salt from sea water

Minerals formed by MetamorphismMinerals formed by Metamorphism When rocks are put under extreme When rocks are put under extreme

heat and pressure, the chemical heat and pressure, the chemical composition of the rock can change, composition of the rock can change, forming new minerals.forming new minerals.

Examples: calcite, garnet, graphite, Examples: calcite, garnet, graphite, hematite, magnetite, mica and talc. hematite, magnetite, mica and talc.

How Are Minerals Identified?How Are Minerals Identified? ColorColor LusterLuster HardnessHardness StreakStreak DensityDensity Crystal ShapeCrystal Shape Cleavage and FractureCleavage and Fracture

Special PropertiesSpecial Properties

ColorColor Usually the first and most easily observedUsually the first and most easily observed

QUARTZROSE QUARTZ SMOKY QUARTZ

- Some minerals are the same color as others- Some minerals are the same color as others

- Some minerals can have many colors- Some minerals can have many colors

Not a reliable way to identify a mineralNot a reliable way to identify a mineral

LusterLuster General appearance of a mineral General appearance of a mineral

surface in reflected lightsurface in reflected light

Glassy-Obsidian

Examples of lusterExamples of luster Metallic

Greasy: resembles the way petroleum jelly or a greasy surface reflects light

Silky: resembles the way silk reflects light

Earthy: dull, may be rough or dusty Waxy

Adamantine: resembles the way a diamond shines

Vitreous: similar to glass Resinous: resembles the way plastic reflects light Pearly: resembles the way pearls shine

Pitchy – looks like tar

Fibrous – looks like fibers

HardnessHardness Resistance to scratching by different Resistance to scratching by different

items; “scratchability”items; “scratchability” Mohs Hardness Scale is used to determine Mohs Hardness Scale is used to determine

the hardness of minerals by comparing the hardness of minerals by comparing them to substances of known hardness.them to substances of known hardness.

Mohs Mineral Hardness Mohs Mineral Hardness ScaleScale

1) Talc 1) Talc

2) Gypsum 2) Gypsum

3) Calcite 3) Calcite

4) Fluorite 4) Fluorite

5) Apatite 5) Apatite

6) Feldspar 6) Feldspar

7) Quartz 7) Quartz

8) Topaz 8) Topaz

9) 9) Corundum Corundum

10) Diamond10) Diamond

Softest

Hardest

1

2

3

4

5

6

7

8

9

10

StreakStreak The color of a finely powdered mineral The color of a finely powdered mineral Determined by rubbing the mineral on a Determined by rubbing the mineral on a

piece of unglazed porcelain (streak plate)piece of unglazed porcelain (streak plate)

DensityDensity The amount of matter in a given space The amount of matter in a given space

Specific Gravity is the comparison of a Specific Gravity is the comparison of a substance’s density to the density of watersubstance’s density to the density of water

Crystal ShapeCrystal Shape Minerals have a Minerals have a

characteristic crystal characteristic crystal shape resulting from shape resulting from the atomic packing of the atomic packing of the atoms when the the atoms when the mineral is formingmineral is forming

Cleavage and FractureCleavage and Fracture CleavageCleavage is the tendency of a is the tendency of a

mineral to split or crack along mineral to split or crack along parallel or flat planes.parallel or flat planes.

BIOTITE QUARTZ Obsidian

No Cleavage 1 Direction of Cleavage

Conchoidal Fracture

FractureFracture occurs when a mineral occurs when a mineral breaks at random lines instead of at breaks at random lines instead of at consistent cleavage planes.consistent cleavage planes.

Fracture

Special Special PropertiesProperties Magnetism (Magnetite)Magnetism (Magnetite)

Taste (Halite)Taste (Halite) Smell (Sulfur)Smell (Sulfur) Reaction to HCl (Calcite)Reaction to HCl (Calcite)

Double refractive - Double refractive - a thin, clear a thin, clear piece of calcite placed over an piece of calcite placed over an image will cause a double imageimage will cause a double image

Radioactivity - minerals containing radium or Radioactivity - minerals containing radium or uranium can be detected by a Geiger counteruranium can be detected by a Geiger counter

Glowing under ultraviolet light (Fluorite)Glowing under ultraviolet light (Fluorite)

Economic Importance of Economic Importance of MineralsMinerals

Minerals are in many things we see Minerals are in many things we see and use everyday such as; bricks, and use everyday such as; bricks, glass, cement, plaster, iron, goldglass, cement, plaster, iron, gold

Every American Requires Every American Requires 40,000 Pounds of New Minerals 40,000 Pounds of New Minerals

per Yearper YearAt this level of consumption the average newborn infant At this level of consumption the average newborn infant

will need a lifetime supply of:will need a lifetime supply of:- 795 lbs of lead (car batteries, electric components)- 795 lbs of lead (car batteries, electric components)- 757 lbs of zinc (to make brass, rubber, paints)- 757 lbs of zinc (to make brass, rubber, paints)- 1500 lbs of copper (electrical motors, wirings- 1500 lbs of copper (electrical motors, wirings- 3593 lbs aluminum (soda cans, aircraft)- 3593 lbs aluminum (soda cans, aircraft)- 32,700 lbs of iron (kitchen utensils, automobiles, - 32,700 lbs of iron (kitchen utensils, automobiles, buildings)buildings)- 28,213 lbs of salt (cooking, detergents)- 28,213 lbs of salt (cooking, detergents)- 1,238,101 lbs of stone, sand, gravel, cement (roads, - 1,238,101 lbs of stone, sand, gravel, cement (roads, homes)homes)