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

What is a Mineral?What is a Mineral?

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

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 ((inorganicinorganic))

3.3. Have a Have a definitedefinite volume and shape volume and shape ((solidsolid) )

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

Watch “Crystals” by Brainpop…

1.What element are diamonds made from?

2. What do all crystals have in common?

Mineral GroupsMineral Groups

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 Groups – SilicatesMineral Groups – Silicates

SilicatesSilicates TetrahedronTetrahedron

fundamental fundamental building blockbuilding block

4 oxygen ions 4 oxygen ions surrounding a surrounding a much smaller much smaller silicon ionsilicon ion

Silicon-oxygentetrahedron

(SiO4)4-

Mineral GroupsMineral Groups

Non-ferromagnesianSilicates (K, Na, Ca, Al)

FerromagnesianSilicates (Fe, Mg)

OxidesCarbonatesSulfides/sulfatesNative elements

Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples

SilicatesSilicates

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

Quartz, micaQuartz, mica

MICA Quartz

Quartz GroupQuartz Group

light silicates (pure SiO2)

no cleavage(conchoidal fracture)

hard, resistant to weatheringQuartz

Feldspar GroupFeldspar Group


light silicates (K, Na, Ca, Al)

2-directionsof cleavage(at 90 degrees)

K-feldspar

Orthoclase

Plagioclase

Ca/Na-feldspar

Pyroxene GroupsPyroxene Groups


dark silicates (Fe-Mg)2 directions of cleavage at nearly 90°

Augite

Amphibole GroupsAmphibole GroupsNon-ferromagnesianSilicates (K, Na, Ca, Al)



dark silicates (Fe-Mg)

2 directions of cleavage not at 90°Hornblende

Mica Group & Clay Mica Group & Clay MineralsMinerals




light silicates (K, Al)

1 direction of cleavage

Shapes of SilicatesShapes of Silicates


Non-Non-SilicatesSilicates

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

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

Silver

GoldRuby Iron

Copper

Diamond


CarbonatesCarbonates Carbon & Carbon & oxygen and a oxygen and a positive 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 Metallic ion, Sulfur ion, Sulfur & oxygen& oxygen

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 rockliquid rock and minerals inside and minerals inside the earth (from the mantle))the earth (from the mantle)) Fast Cooling = No Crystals Fast Cooling = No Crystals (mineraloids)(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

(can be used to identify the (can be used to identify the mineral)mineral)

ColorColor LusterLuster Habit (Shape)Habit (Shape) Cleavage & FractureCleavage & Fracture StreakStreak HardnessHardness OtherOther

ColorColor- Most obvious, Most obvious, but often but often misleadingmisleading

- Different colors Different colors may result from may result from impurities; ie., impurities; ie., Quartz Quartz

LusterLuster Surface Surface reflectionreflection

metallic = shiny metallic = shiny like metallike metal

non-metallic = non-metallic = dull, non-shiny dull, non-shiny surfacesurface

Metallic - pyrite

Non-metallic - calcite

Mineral Habit (Shape)Mineral Habit (Shape)

Shape a mineral Shape a mineral takes if grown takes if grown unimpededunimpeded

http://www.minerals.net/MineralImageGallery.aspx

Amethyst

Babingtonite

Diamond

Fluorite

Cleavage & FractureCleavage & Fracture The way the mineral The way the mineral breaksbreaks

CleavageCleavage—minerals break —minerals break along along smoothsmooth, flat , flat surfaces and every surfaces and every fragment has the same fragment has the same general shapegeneral shape

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

Cleavage or Fracture?Cleavage or Fracture?1.

4.

3.

2.

StreakStreak The The colorcolor of the powdered of the powdered form of the mineralform of the mineral

The color of the streak The color of the streak can be different than the can be different than the mineralmineral

Minerals must be Minerals must be softersofter than the streak platethan the streak plate

Streak…can help identify Streak…can help identify quartzquartz

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

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 Test by seeing if the mineral can scratch different objects (like human scratch different objects (like human fingernail, copper, penny, glass, fingernail, copper, penny, glass, steel file)steel file)

Find out more…Find out more…

““Electronic” Hardness TestElectronic” Hardness Test

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

Other PropertiesOther Properties Specific gravity (*excellent clue Specific gravity (*excellent clue to mineral’s identity)to mineral’s identity)

Attraction to Attraction to magnetsmagnets

Bending of lightBending of light

Reaction with hydrochloric acidReaction with hydrochloric acid

Smell & tasteSmell & taste

Watch Brainpop—“Mineral Identification”

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

2. What is luster?

Watch Classifying Minerals ClipWatch Classifying Minerals Clip

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