Post on 27-Mar-2015
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))
What do all minerals What do all minerals have in common?have in common?
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.
What do all minerals What do all minerals have in common?have in common?
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
What do all minerals What do all minerals have in common?have in common?
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.
What do all minerals What do all minerals have in common?have in common?
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.
What do all minerals What do all minerals have in common?have in common?
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?
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
Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples
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
Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples
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
Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples
OxidesOxides Metallic ion Metallic ion and oxygenand oxygen
Hematite Hematite (Fe(Fe22)O)O33
Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples
SulfidesSulfides Sulfur and a Sulfur and a metallic ionmetallic ion
Galena (PbS)Galena (PbS)
Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples
SulfatesSulfates Metallic ion, Metallic ion, Sulfur & Sulfur & oxygenoxygen
Barite Barite (BaSO(BaSO44))
Barite on Calcite BaSo4 / CaCO3
BariteBaSo4
Mineral GroupMineral Group CharacteristicsCharacteristics ExamplesExamples
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
Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)
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
Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)
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
Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)
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
Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)
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
Physical Properties of MineralsPhysical Properties of Minerals (can be used to identify the mineral)(can be used to identify the mineral)
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?