What is a Mineral? Naturally-formed solid substance with a crystal structure Naturally-formed solid...

What is a Mineral?What is a Mineral?

Naturally-formed Naturally-formed solidsolid substance substance with a with a crystalcrystal structure structure

Pyromorphite

What do all minerals What do all minerals have in common?have in common?

All:All:1.1. Are formed by Are formed by naturalnatural processes. processes.

2.2. Are Are NOTNOT alive and NEVER were alive alive and NEVER were alive

3.3. Have a Have a definitedefinite volume and shape volume and shape

4.4. Are elements or compounds with a Are elements or compounds with a uniqueunique chemical makeupchemical makeup

5.5. Are made up of particles that are arranged Are made up of particles that are arranged in a pattern that is repeated over and over in a pattern that is repeated over and over (called a (called a CRYSTALCRYSTAL))


They must occur They must occur naturally within the naturally within the earth. earth.

Cement, bricks, Cement, bricks, steel, and glass are steel, and glass are not minerals not minerals because they are because they are man made.man made.


Minerals must be Minerals must be inorganic. This means inorganic. This means that they cannot arise that they cannot arise from materials that from materials that were once part of a were once part of a living thing.living thing.

Coal is not a mineral Coal is not a mineral because it comes because it comes from the remains of from the remains of plants and animalsplants and animals


Minerals have a Minerals have a definite volume definite volume and shape.and shape.

The particles that The particles that make up the make up the sample do not sample do not move apart.move apart.


Minerals have definite Minerals have definite chemical compositions. chemical compositions.

A mineral always contains A mineral always contains certain elements in certain elements in definite proportions.definite proportions.

Most minerals are Most minerals are compounds. compounds.

Compounds are two or Compounds are two or more elements combined. more elements combined.

Some minerals are just Some minerals are just elements Copper, Gold, elements Copper, Gold, and Silver.and Silver.


Minerals have crystal Minerals have crystal structures. These are structures. These are particles in minerals particles in minerals that line up in a that line up in a pattern that repeats pattern that repeats over and over again.over and over again.

Sometimes a crystal Sometimes a crystal structure is obvious structure is obvious and sometimes its and sometimes its only visible under a only visible under a microscope.microscope.

Watch “Crystals” by Brainpop…

1.What element are diamonds made from?

2. What do all crystals have in common?

http://www.brainpop.com/science/theearthsystem/crystals/

Groups of MineralsGroups of Minerals

Minerals are grouped by the Minerals are grouped by the elements they are made of.elements they are made of.

Amethyst

Beryl (Emerald) Calcite

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

SilicatesSilicates

Contain Contain oxygenoxygen & & silicasilicaThe most The most abundantabundant group of group of mineralsminerals

Quartz, micaQuartz, mica

MICA Quartz


Non-SilicatesNon-Silicates

Make up only Make up only 5%5% of the of the Earth’s crustEarth’s crustInclude some Include some of the most of the most important important mineralsminerals

iron, copper, iron, copper, gold, silver, gold, silver, diamonds, diamonds, rubiesrubies

Silver

GoldRuby Iron

Copper

Diamond


CarbonatesCarbonates Carbon & Carbon & oxygen and oxygen and a positive a positive ion, such as ion, such as calciumcalcium

Calcite Calcite (CaCO(CaCO33))

Calcite with Duftite inclusions


OxidesOxides Metallic ion Metallic ion and oxygenand oxygen

Hematite Hematite (Fe(Fe22)O)O33


SulfidesSulfides Sulfur and a Sulfur and a metallic ionmetallic ion

Galena (PbS)Galena (PbS)


SulfatesSulfates Metallic ion, Metallic ion, Sulfur & Sulfur & oxygenoxygen

Barite Barite (BaSO(BaSO44))

Barite on Calcite BaSo4 / CaCO3

BariteBaSo4


Native Native ElementsElements

Single Single elementselements

Gold (Au), Gold (Au), Diamond (C), Diamond (C), Silver (Ag)Silver (Ag)

How do minerals form?How do minerals form?

1) Cooling of 1) Cooling of magmamagma (hot, (hot, liquid liquid rockrock and minerals inside the earth and minerals inside the earth (from the mantle))(from the mantle)) Fast Cooling = No Crystals (mineraloids)Fast Cooling = No Crystals (mineraloids) Medium Cooling = small crystalsMedium Cooling = small crystals Slow Cooling = large crystalsSlow Cooling = large crystals

How do minerals form?How do minerals form?

2) Elements dissolved in 2) Elements dissolved in liquidsliquids (usually water)(usually water)

Physical Properties of Physical Properties of MineralsMinerals

Mineral appearance Mineral appearance HardnessHardness LusterLuster Specific gravitySpecific gravity StreakStreak Cleavage Cleavage andand fracture fracture

Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)

ColorColor Can be Can be misleadingmisleading Can vary with the type of impuritiesCan vary with the type of impurities


HardnessHardness How easily a mineral How easily a mineral scratchesscratches

materialsmaterials Mohs Hardness ScaleMohs Hardness Scale

Scale from 1 (Scale from 1 (softestsoftest) to 10 () to 10 (hardesthardest)) Test by seeing if the mineral can scratch Test by seeing if the mineral can scratch

different objects (like human fingernail, different objects (like human fingernail, copper, penny, glass, steel file)copper, penny, glass, steel file)

Properties of MineralsProperties of MineralsMohs Hardness Scale

MineralTalc

Gypsum

Calcite

Fluorite

Apatite

Feldspar

Quartz

Topaz

Corundum

Diamond

Rating1 Softest known mineral. It flakes

easily when scratched by a fingernail.

2 A fingernail can easily scratch it.

3 A fingernail cannot scratch it, but a copper penny can.

4 A steel knife can easily scratch it.

5 A steel knife can scratch it.

6 Cannot be scratched by a steel knife, but it can scratch window glass.

7 Can scratch steel and hard glass easily.

8 Can scratch quartz.

9 Can scratch topaz.

10 Hardest known mineral. Diamond can scratch all other substances.

Testing Method

Find out more…Find out more…

““Electronic” Hardness TestElectronic” Hardness Test

http://www.childrensmuseum.org/http://www.childrensmuseum.org/geomysteries/cube/b2.html geomysteries/cube/b2.html


LusterLuster Surface Surface reflectionreflection metallic = shiny metallic = shiny

like metallike metal non-metallic = non-metallic =

dull, non-shiny dull, non-shiny surfacesurface

Pyrite has a metallic luster

Calcite has a non-metallic luster

Specific Gravity or Specific Gravity or DensityDensity

The specific gravity of a mineral is The specific gravity of a mineral is

the ratio of its mass the ratio of its mass comparedcompared with the mass of an equal volume of with the mass of an equal volume of water.water.

Gold has specific gravity of Gold has specific gravity of 1919 It means gold is It means gold is 19 times heavier19 times heavier

than water.than water.19 times heavier

DensityDensity


StreakStreak The The colorcolor of the powdered of the powdered

form of the mineralform of the mineral The color of the streak can The color of the streak can

be different than the mineralbe different than the mineral Minerals must be Minerals must be softersofter than than

the streak platethe streak plate

Streak…can help identify Streak…can help identify quartzquartz

http://www.childrensmuseum.org/geomysteries/cube/b3.html


Cleavage & FractureCleavage & Fracture The way the mineral The way the mineral breaksbreaks CleavageCleavage—minerals break —minerals break

along along smoothsmooth, flat surfaces , flat surfaces and every fragment has the and every fragment has the same general shapesame general shape

FractureFracture—minerals that —minerals that break at break at randomrandom with rough with rough or jagged edgesor jagged edges

CleavageCleavage

CleavageCleavage is the way that mineral is the way that mineral breaks.breaks.

Minerals that break along smooth, Minerals that break along smooth, flat surfaces have cleavage.flat surfaces have cleavage.

Mica has cleavageMica has cleavage

and and Fracture!...Fracture!... Mineral that breaks uneven, rough, Mineral that breaks uneven, rough,

or jagged surfaces have fracture.or jagged surfaces have fracture. Quartz has fractureQuartz has fracture

quartzquartz

Identify the minerals below Identify the minerals below for cleavage and fracturefor cleavage and fractureCLEAVAGECLEAVAGE FRACTUREFRACTURE

in


Other PropertiesOther Properties Specific gravity (*excellent clue to Specific gravity (*excellent clue to

mineral’s identity)mineral’s identity) Attraction to Attraction to magnetsmagnets Bending of lightBending of light Reaction with hydrochloric acidReaction with hydrochloric acid Smell & tasteSmell & taste

http://www.childrensmuseum.org/geomysteries/cube/b4.html

An illustration An illustration appearance:luster,color and appearance:luster,color and

streakstreak

An illustration An illustration cleavage and fracturecleavage and fracture

Watch Classifying Minerals ClipWatch Classifying Minerals Clip

Watch Brainpop—“Mineral Identification”

1. If a mineral can scratch your fingernail, the mineral is _______________ than your fingernail.

2. What is luster?

What is a Mineral? Naturally-formed solid substance with a crystal structure Naturally-formed solid...

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