Minerals - Part IIMinerals - Part II

7 Major mineral groups7 Major mineral groups

Nature’s most common building block in Nature’s most common building block in rock forming minerals is the …rock forming minerals is the …

Silica Tetrahedra SiOSilica Tetrahedra SiO44

1) Silicate Minerals1) Silicate Minerals

Quartz is the Quartz is the secondsecond most abundantmost abundant mineral on the mineral on the earth’s crustearth’s crust

(the most abundant element on the (the most abundant element on the earth’s crust is therefore earth’s crust is therefore oxygenoxygen))

Quartz is used for Quartz is used for glass, jewelry and glass, jewelry and electronicselectronics

FeldsparsFeldspars

Feldspar is the Feldspar is the

most abundant most abundant

““family” of minerals family” of minerals

on the earth’s crust. on the earth’s crust.

The various feldspar The various feldspar

minerals make up minerals make up

over over 60 percent60 percent of the crust. of the crust. ((AluminumAluminum ions replace silicon ions) ions replace silicon ions)

FeldsparsFeldspars

Feldspar is used for Feldspar is used for ceramics (china) and ceramics (china) and glassglass

MicasMicas Micas are soft Micas are soft

silicates found in silicates found in many rocks - many rocks - micas most micas most distinctive feature distinctive feature is that it has is that it has oneone cleavage surface – cleavage surface – they are pearly and they are pearly and ‘flake’ easily ‘flake’ easily

Micas Micas

Micas are used for Micas are used for

electronic electronic insulationinsulation

AmphibolesAmphiboles

– – complex complex type in the type in the silica group silica group where iron where iron and and magnesiumagnesium have m have replaced a replaced a silicasilica ion. ion.

CarbonatesCarbonatesCarbonate mineral group is made up of Carbonate mineral group is made up of compoundscompounds of of one carbon one carbon andand 3 oxygen 3 oxygen atoms (COatoms (CO33) joined with various metal ions) joined with various metal ions

CarbonatesCarbonates

reactreact with acid (HCl); with acid (HCl); calcite reacts calcite reacts strongly with acid, strongly with acid, other carbonate other carbonate minerals react only minerals react only mildly with acid.mildly with acid.

Other Carbonate MineralsOther Carbonate Minerals

Dolomite = Dolomite = CaMg(COCaMg(CO33))22

Siderite = FeCOSiderite = FeCO33

OxidesOxidesMetalMetal + oxygen = oxide + oxygen = oxide For example: For example: Hematite = FeHematite = Fe22OO33

Franklinite = Franklinite = (Zn,Mn,Fe)(Zn,Mn,Fe)22+ (Fe,Mn)+ (Fe,Mn)33+2O+2O44

SulfidesSulfides

MetalMetal + sulfur = + sulfur = sulfidesulfide

For Example: For Example: Pyrite = FeSPyrite = FeS22

SulfatesSulfates

SulfurSulfur + 4 Oxygen + 4 Oxygen atoms = Sulfate atoms = Sulfate SOSO44

For example: For example: Barite = BaSOBarite = BaSO44

Halites (Salts)Halites (Salts)

Compounds of elements and chlorine, Compounds of elements and chlorine, fluorine, iodine or brominefluorine, iodine or bromine

For example: For example:

table salttable salt = NaCl, = NaCl,

potassium salt = KClpotassium salt = KCl

Native ElementsNative Elements Elements found Elements found uncombineduncombined with other with other

elements, For example:elements, For example:goldgold

silversilver

coppercopper

sulfursulfur

diamonddiamond

7 Mineral Groups 7 Mineral Groups (in relative order of abundance)(in relative order of abundance)

1.1. SilicatesSilicates – minerals that contain silicon & – minerals that contain silicon & oxygen, and usually one more elementoxygen, and usually one more element

2.2. CarbonatesCarbonates – contains carbon w/3 oxygen – contains carbon w/3 oxygen atomsatoms

3.3. SulfatesSulfates – contains sulfur w/four oxygen – contains sulfur w/four oxygen atomsatoms

4.4. HalidesHalides – compounds of certain elements and – compounds of certain elements and chlorine, fluorine, iodine or brominechlorine, fluorine, iodine or bromine

5.5. OxidesOxides – compounds of elements and oxygen – compounds of elements and oxygen (usually rust looking)(usually rust looking)

6.6. SulfidesSulfides – compounds of elements and sulfur – compounds of elements and sulfur7.7. Native ElementsNative Elements – elements found – elements found

uncombined w/other elements (copper, gold, uncombined w/other elements (copper, gold, etc…)etc…)

Single chain silicates… Single chain silicates…

End hereEnd here

Look familiar?Look familiar?

Felspar…Felspar…

MicroclineMicrocline

Distinguishing Distinguishing feature:feature:

the the ‘laminae’ – ‘laminae’ – little veins in little veins in the mineralthe mineral

GarnetGarnet

CaCa33AlAl22(SiO(SiO44))33

Look familiar?Look familiar? Hornblende:Hornblende:

striated striated appearance appearance

hexagonal cross-hexagonal cross-section section

Dark-dark green Dark-dark green to blackto black

Look familiar?Look familiar?

MagnetiteMagnetite magneticmagnetic

Look familiar?Look familiar?

OlivineOlivine Light to dark greenLight to dark green Really hard (6.5-7)Really hard (6.5-7)

Look familiar?Look familiar?

FrankliniteFranklinite Stubby metallic Stubby metallic

crystals, usually crystals, usually in calcitein calcite

Look familiar?Look familiar?

ZinciteZincite redred vitreousvitreous orange-yellow orange-yellow

streakstreak

WillmeniteWillmenite greengreen strongly fluorescent strongly fluorescent

green green