minerals
DESCRIPTION
GeologyTRANSCRIPT
-
6/11/2013
1
L3 - MINERALS
CIVE 430 ENGINEERING GEOLOGY
SUMMER 2013
DEFINITION Theearth,theotherinnerplanetsandthemoonare
madeofROCKS. Rocksinturn,aremadeofMINERALS
MINERALSare: Solids;naturalcompoundsANDtheyhave AregularstructuremadeofATOMSheldtogetherby
electromagneticforces Afixedchemicalcomposition.
-
6/11/2013
2
WhatisaMineral?
PeriodicTable http://www.webelements.com/
-
6/11/2013
3
MineralClassificationMineralsofonetypeofatom nativeelements(Augold,Ag silver,Cu copper,)
MineralswithCationscombinedwiththelarge,negativeions(anions): oxygen(O oxides),sulfur(S sulfides),halogens(Cl,ForBr halides).
Aniongroupsmadeofoxygen combinedwithcationsofvalency+3orgreater(seeperiodictablenonmetalsofgroups1317):silicates(SiO4),carbonates(CO3)andsulfates(SO4).
MineralStructureThisarrangement,knownasCrystalStructure isdeterminedby: Theatomsize TheTypesofBonds:ionic,covalent,VanderWaals
-
6/11/2013
4
Howaremineral'sformedinnature? Fromawatersolution.Thechemicalsinthesolutioncome
fromdissolvingotherminerals.Thesemineralsformatthesurfaceoftheearthaswaterevaporates(sedimentary)orfromhotwaterinsidetheearthasthatwatercools(hydrothermal).
Fromasilicatemelt. Themeltcomesfrommeltingminerals.Thesemineralsform:Wheremoltenrockcools eitherintheinteriororatthesurface(igneous).
Byaddingenergytominerals,rearrangetheionsoftheoldstructureandmakeanewone.
ThesemineralsformInsidetheearthwherehightemperaturesprovidethenecessaryenergy(metamorphic).
PHYSICALCHARACTERISTICSOFMINERALS
Color Luster Cleavage Fracture Hardness SpecificGravity Streak
-
6/11/2013
5
PHYSICALCHARACTERISTICSOFMINERALS
COLOR: Cobalt,Co,produces: violetred Chromium,Cr,produces: orangered Copper,Cu,produces: azureblue Iron,Fe,produces: red Manganese,Mn,produces: pink Nickel,Ni,produces: green Uranium,U,produces: yellow Vanadium,V,produces: Redorange
PHYSICALCHARACTERISTICSOFMINERALSSTREAK: Colorofthemineralmaybe
differentthanthecolorofthestreak.Streakisactuallythecolorofthepowderofamineral
Properwaytotestforstreakistorubamineralacrossatileofwhiteporcelainandtoexaminethecolorofthe"streak"leftbehind
HEMATITE
StreakisBloodRED
-
6/11/2013
6
PHYSICALCHARACTERISTICSOFMINERALSSTREAK
HEMATITE
Streak is Blood RED
PHYSICALCHARACTERISTICSOFMINERALSLUSTER
Descriptionofthewaylightinteractswiththesurfaceofacrystal.Ithasnothingtodowithcolororshape,butisrelatedtotransparencyandsurfaceconditions.
Dull justanonreflectivesurfaceofanykind Earthy thelookofdirtordriedmud Fibrous thelookoffibers Greasy thelookofgrease Metallic thelookofmetals Pearly thelookofapearl Pitchy thelookoftar Resinous thelookofresinssuchasdriedglueorchewinggum Vitreous simplymeansthelookofglass Waxy thelookofwax
-
6/11/2013
7
PHYSICALCHARACTERISTICSOFMINERALSLUSTER FibrousAsbestos
CLEAVAGE Crystalcleavageisasmoothbreakproducingwhatappearstobeaflatcrystalface
cleavageisreproducible thesamemineralwillalwayshavethesamecleavage.
CALCITECleavageisperfectin3directions,formingrhombohedrons
PHYSICALCHARACTERISTICSOFMINERALS
-
6/11/2013
8
Cleavage.GemsSalt
PHYSICALCHARACTERISTICSOFMINERALS
NoCleavageConcoidalFractureOBSIDIAN
Salt
FRACTURE
PHYSICALCHARACTERISTICSOFMINERALS
-
6/11/2013
9
HARDNESS Hardnessisameasureofthestrength
ofthestructureofthemineralrelativetothestrengthofitschemicalbonds
Hardnesscanbetestedthroughscratching.Groovesrequireeitherthebreakingofbondsorthedisplacementofatoms. Ahardmineralcanscratchasoftermineral,butasoftmineralcannotscratchahardermineral.
TheMohs HardnessScale DiamondMhoHardness=10
PHYSICALCHARACTERISTICSOFMINERALS
MhosHardnessScale1. Talc2. Gypsum3. Calcite4. Fluorite5. Apatite6. Orthoclase7. Quartz8. Topaz9. Corundum(rubyandsapphire)10.Diamond
PHYSICALCHARACTERISTICSOFMINERALS
-
6/11/2013
10
Mhos Scale
MhosScale
-
6/11/2013
11
DiamondStructure
Diamond Structure
-
6/11/2013
12
DENSITY SPECIFICGRAVITY Gold caneasilybedistinguishedfrom
"fool'sgold" byspecificgravityalone SGorGs =Densityofthemineral
dividedbythedensityofwater TheEarth'scrust,wherewearemost
likelytocollectmineralsfrom,iscomposedmostlyofthemineralsquartz,calcite andfeldspar. ThesemineralshaveSG'saround2.7
PHYSICALCHARACTERISTICSOFMINERALS
Rock Forming MineralsOxides (containing O2-)-SAPPHIRE (Corundum)
Sulfides (containing S2-)-GALENA
Sulfates (containing SO42-)-GYPSUM
Native Elements-SILVER
Halides (salts)-FLUORITE
Carbonates (containing CO32-)-CALCITE
Hydroxides (containing OH-)-MANGANITE
Phosphates (containing PO43-)-FLUORAPATITE
SILICATES (containing SiO44-)
-
6/11/2013
13
Rock Forming Minerals
RockFormingMineralsCarbonates
-
6/11/2013
14
Rock Forming MineralsCarbonates
Rock Forming MineralsSilicate MineralsForm 95% of the Earth's crust
>80% of the Earth's mantle
Why?
-
6/11/2013
15
RockFormingMineralsSilicateMinerals Quartz Feldspars(Orthoclase,Plagioclase) Mica(Muscovite,Biotite) Clay(Kaolinite,Montmorillonite) OlivineAmphibolePyroxine (Groups) Garnet Serpentine
RockFormingMineralsSilicateStructure
-
6/11/2013
16
RockFormingMineralsSheetStructure Mica
RockFormingMineralsSilicateMinerals
Feldspar Mica
PyroxeneQuartzOlivine
-
6/11/2013
17
RockFormingMineralsNonSilicateMinerals
Halite Spinel
CalcitePyriteGalena
Gypsum
Hematite