Minerals 1a.ppt

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))

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)

http://www.gc.maricopa.edu/earthsci/imagearchive/gold.jpg

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 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


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


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




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)

Find out more…Find out more…

““Electronic” Hardness TestElectronic” Hardness Test

http://www.childrensmuseum.org/geohttp://www.childrensmuseum.org/geomysteries/cube/b2.htmlmysteries/cube/b2.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

Cleavage or Fracture?Cleavage or Fracture?1.

4.

3.

2.

http://www.pitt.edu/~cejones/GeoImages/1Minerals/2SedimentaryMineralz/Calcite_Dolomite/CalciteChunk.jpg


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




Watch Brainpop—“Mineral Identification”

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

2. What is luster?

Watch Watch Classifying Minerals Classifying Minerals ClipClip

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Minerals 1a.ppt