Modul 5a - Minerals, Definition & Classes [versi english]

8/9/2019 Modul 5a - Minerals, Definition & Classes [versi english]

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Minerals


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What is a Mineral? What is a Mineral? A mineral is a naturally formed inorganic crystalline solidA mineral is a naturally formed inorganic crystalline solidwith a definite chemical composition and identifyingwith a definite chemical composition and identifyingphysical propertiesphysical properties

naturally formednaturally formedformed by geologic processes in nature, not by humansformed by geologic processes in nature, not by humans

inorganicinorganicwas never alivewas never alive

crystalline solidcrystalline solid

a solid composed of atoms arranged in a repeating orderlya solid composed of atoms arranged in a repeating orderlyframeworkframework

definite chemical compositiondefinite chemical compositiona homogeneous chemical compound with a chemical formulaa homogeneous chemical compound with a chemical formula

distinctive, identifying physical propertiesdistinctive, identifying physical properties

Definition


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Definition

What is a Mineral? What is a Mineral? Is water a mineral?Is water a mineral?

Why or why not?Why or why not?Is ice a mineral?Is ice a mineral?

Why or why not?Why or why not?Is glass a mineral?Is glass a mineral?

Why or why not?Why or why not?Is gold a mineral?Is gold a mineral?

Why or why not?Why or why not?Is steel a mineral?Is steel a mineral?

Why or why not?Why or why not?


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Definition

Mineral is a naturally occurring inorganic element or compound having orderly internal structure andcharacteristic chemical composition, crystal form, andphysical properties

Pertanyaan:Apakah lampu kristal tergolong mineral?Bagaimana dengan tubuh kekurangan mineral?

Air mineral?


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Mineral is a structurally homogeneous solid of definitechemical composition, formed by the inorganicprocesses of nature.

Whitten, DGA and Brooks, JRV. 1977. The Penguin Dictionary of Geology . Middlesex: Penguin Books. p. 293.

Definition


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This definition includes ice as a mineral, but excludescoal, natural oil and gas. T he only allowable exceptionto the rule that a mineral must be solid is nativemercury (quicksilver), which is liquid.Definite chemical composition is not synonymous withfixed or constant composition, since many mineralshave compositions which are variable between certainlimits, which are defined in terms of end members: e.g.the composition of the common olivines is expressible interms of the two compounds, Mg 2SiO 4 (forsterite) andFe 2SiO 4 (fayalite). T he general rule is that minor variations of composition which do not markedly alter fundamental properties are discounted

Definition


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Structurally homogeneous implies that the fundamentalatomic structure is continuous and constant through themineral unit, e.g. in silicates the silicon-oxygen latticewill be constant in characters, although the interstitialcations may vary in different parts of the lattice

Although strictly of organic origin , the constituents of many limestones, siliceous rocks, and beddedphosphate deposits are treated as though they were truemineral species

Whitten, DGA and Brooks, JRV. 1977. The Penguin Dictionary of Geology . Middlesex: Penguin Books. p. 293-294.

Definition


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E lectron-bearing shells

Model of Oxygen

Review


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Review

2 protons in nucleus

10 protons in nucleus

Model of Helium (He)

Model of Neon (Ne)


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Model of Sodium (Na+)

Model of Chlorine (Cl-)

Review


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Model of crystalline structure of Halite (salt)

Ionic Bonding:Electron Transfer

Review

Chlorine (Cl)

Sodium (Na)

Sodium(Na+) ion

Chlorine(Cl ) ion


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Mineral Structures and Atoms

Model of crystalline structure

Review


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E lemental Abundances in Continental Crust E lemental Abundances in Continental Crust


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ELE ME NT YANG M ELI MPAH D I KE RAK BUM I

E lement Simbol % Berat % Volume % Atom

Oksigen O 46,6 93,8 60,5Silikon Si 27,7 0,9 20,5Aluminium Al 8,1 0,8 6,2Besi Fe 5,0 0,5 1,9Kalsium Ca 3,6 1,0 1,9Sodium Na 2,8 1,2 2,5Potasium K 2,6 1,5 1,8Magnesium Mg 2,1 0,3 1,4Semua element lain 1,5 - 3,3


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Mineral ClassesMineral Classes

Silicate Mineral GroupSilicate Mineral Group

NonNon--silicate Mineralsilicate MineralGroupGroup


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S ilicate Mineral GroupsS ilicate minerals (silicates) are composed of silica tetrahedra ( S iO 4 4- )

For silica tetrahedra to be stable, they must either:be balanced by positive ions,share oxygens with adjacent silica tetrahedra, or substitute one or more Al 3+ for Si 4+

Compositions of the silicatesM afic composition

Is rich in magnesium, iron, and/or calciumI ntermediate composition

Is compositionally between mafic and felsicIs rich in feldspar and/or silica (quartz)

F elsic compositionIs rich in feldspar and/or silica (quartz)

All the common rock-forming minerals are silicate mineral


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T he S ilica T etrahedronT he S ilica T etrahedron(composed of 4 oxygen atoms surrounding 1 silicon atom)(composed of 4 oxygen atoms surrounding 1 silicon atom)

S ilicate Mineral Groups


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TwoTwo Illustrations Illustrations

of theof theSi SiOO 44

TetrahedronTetrahedron



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S ingle Island S ilicatesS ingle Island S ilicates(ex.: olivine)(ex.: olivine)

S ingle Chain S ilicatesS ingle Chain S ilicates(ex.: augite pyroxene)(ex.: augite pyroxene)



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S ingle Chain S ilicates: T he Pyroxenes (e.g., augite)S ingle Chain S ilicates: T he Pyroxenes (e.g., augite)



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D ouble Chain S ilicates: T he AmphibolesD ouble Chain S ilicates: T he Amphiboles(e.g., hornblende)(e.g., hornblende)



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S heet S ilicates: T he MicasS heet S ilicates: T he Micas(e.g., biotite, muscovite, and the clays)(e.g., biotite, muscovite, and the clays)

Because of weak bonds,mica splits asily betweensandwiches

Positive ions, sandwichesbetween two sheetssilicate layers

Sheet silicate structure

E xample :Clay groupsMica groups



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F ramework S ilicates:F ramework S ilicates:(potassium feldspar, sodium and calcium plagioclase feldspar, quartz)(potassium feldspar, sodium and calcium plagioclase feldspar, quartz)



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T he Common Rock T he Common Rock- - F orming S ilicate MineralsF orming S ilicate Minerals



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N on-silicate Mineral Groups

Native E lementsNative E lements : consist of only one element.: consist of only one element.Au (gold), Ag (silver), Cu (copper), S (sulfur), C (graphite,Au (gold), Ag (silver), Cu (copper), S (sulfur), C (graphite,diamond)diamond)

OxidesOxides : contain O: contain O 22--FeFe 22OO 33 (hematite), Fe(hematite), Fe 33OO 44 (magnetite), Al(magnetite), Al 22OO 33 (corundum)(corundum)

CarbonatesCarbonates : contain CO: contain CO 33 22--CaCOCaCO 33 (calcite), CaMg(CO(calcite), CaMg(CO 33))22 (dolomite)(dolomite)

SulfidesSulfides : contain S: contain S 22--FeSFeS 22 (pyrite), PbS (galena), CuFeS(pyrite), PbS (galena), CuFeS 22 (chalcopyrite)(chalcopyrite)

SulfatesSulfates : contain SO: contain SO 4422--

CaSOCaSO 44.2H.2H 22O (gypsum), BaSOO (gypsum), BaSO 44 (barite)(barite)

HalidesHalides : contain F: contain F 11--, Cl, Cl 11--, Br , Br 11--, or I , or I 11--NaCl (halite), KCl (sylvite), CaFNaCl (halite), KCl (sylvite), CaF 22 (fluorite)(fluorite)


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N ative Copper N ative Copper



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By crystallization from magma (molten rock material)By crystallization from magma (molten rock material)

a saturation responsea saturation responseBy crystallization (precipitation) from aqueous fluidsBy crystallization (precipitation) from aqueous fluids

a saturation responsea saturation responseBy chemical reaction withBy chemical reaction with

magmatic fluidsmagmatic fluidshydrothermal fluidshydrothermal fluidswater during weatheringwater during weathering

By solid state transformations (metamorphism)By solid state transformations (metamorphism)changes crystal formchanges crystal form

moves ions to new locationsmoves ions to new locationspromotes growth along the edges of mineral grains (crystals)promotes growth along the edges of mineral grains (crystals)at the expense of their neighboring mineral grainsat the expense of their neighboring mineral grains

How do minerals form?


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Crystallization of Minerals in Cavities: GeodesCrystallization of Minerals in Cavities: Geodes



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T he E ffect of Crowding on Crystal GrowthT he E ffect of Crowding on Crystal Growth



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PolymorphsPolymorphs

Polymorphs are minerals that have the same chemicalPolymorphs are minerals that have the same chemicalcomposition but a different crystal formcomposition but a different crystal formGraphite and diamond polymorphs of carbonGraphite and diamond polymorphs of carbon

Graphite forms at low temperature and pressureGraphite forms at low temperature and pressure

Diamond forms at high temperature and pressureDiamond forms at high temperature and pressureQuartz, stishovite, and coesite are polymorphs of SiOQuartz, stishovite, and coesite are polymorphs of SiO 22

Quartz forms at low to medium temperature and pressureQuartz forms at low to medium temperature and pressurestishovite and coesite form at high pressure, such as thatstishovite and coesite form at high pressure, such as thatassociated with meteor impactsassociated with meteor impacts

Andelusite, kyanite, and sillimanite are polymorphs of AlAndelusite, kyanite, and sillimanite are polymorphs of Al 22SiOSiO 55Andelusite is the low temperature low pressure polymorphAndelusite is the low temperature low pressure polymorphKyanite is the low temperature high pressure polymorphKyanite is the low temperature high pressure polymorphSillimanite is the high temperature high pressure polymorphSillimanite is the high temperature high pressure polymorph



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PseudomorphsPseudomorphsPseudomorphs are minerals that have the same crystal form butPseudomorphs are minerals that have the same crystal form buta different chemical compositiona different chemical composition

L imonite forms cubic pseudomorphs after pyriteL imonite forms cubic pseudomorphs after pyrite

Quartz forms pseudomorphs after fluoriteQuartz forms pseudomorphs after fluorite



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Modul 5a - Minerals, Definition & Classes [versi english]

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