Minerals Bauxite (Al(OH)3nH20) Chalcopyrite (CuFeS2) Gold (Au) Beverage cansElectrical WiresJewelry; Cell phoneUse of minerals Gold (Au) Graphite (C) Diamond (C) Chromite (FeCr204) Ruby Jewelry; Cell phoneCircuitryLead PencilDentists drillChrome platingLasers Quartz (SiO2) Gypsum (CaSO4) Sulfur (S)Glass; Watch componentPlaster; Taho?Sulfa drugs, Foot powderUse of minerals Sulfur (S) Galena (PbS) Calcite (CaCO3) Fluorite (CaF2) Silver (Ag) Sulfa drugs, Foot powderLead plating (x-rays)CementFlux in steel makingPhotographic filmUse of minerals Practically every manufactured product is derived from a mineral! Definition of a mineral1. Naturally occurring2. Inorganic3. Solid 3. Solid4. Ordered internal structure5. Definite chemical composition (may vary only very slightly)Naturally occurring Should not be synthesized Synthetic diamond Ceramics synthesized by chemists and engineersInorganic Should not have been produced by an organism Skeletons of Skeletons of animals Shells of molluscs Whewellite (kidney stones)Solid Liquids are not allowed Mercury (Hg) Mercury (Hg) Ice is a mineral but liquid water is notOrdered internal structure Atoms comprising the mineral are arranged in an ordered fashion Glass does not have any ordered structureDefinite chemical composition Can vary only slightly e.g. Olivine Fe2SiO4 Mg2SiO4The ions Fe+2and Mg+2can substitute each other at specific lattice points Mg2SiO4lattice pointsDefinite chemical compositionCan bring about the different varieties in color of a mineralMinerals In the strict sense should satisfy the 5 parts of the definition If some are not satisfied then they are called If some are not satisfied then they are called mineraloidsBasic structure of atomTypes of bondsPrimary bonding forces IonicSecondary bonding forces Ionic Covalent Metallic Van der Waals Hydrogen bondingIonic bondElectrons are transferred to form a bondCovalent bondingElectrons are shared to form a bondPhysical propertieseach mineral is characterized by a unique set of physical properties1. Crystal form2. Luster3. Color4. Streak5. Hardness6. Cleavage7. Fracture8. Specific GravityOthersCrystal form External expression of a mineral that reflects the ordered internal structure of a mineral structure of a mineral Cubic Octahedron Rhombic Hexagonal DodecahedronLuster The appearance or quality of light reflected from the surface of a mineral surface of a mineral Adamantine Glassy Pearly Greasy MetallicColor A phenomenon of light by which otherwise identical objects may beobjects may be differentiated Red Blue Green YellowStreak The color of a mineral in powdered form Blue Green Yellow RedHardness1. Talc2. Gypsum3. Calcite4. Fluorite A minerals resistance to scratching and abrasion4. Fluorite5. Apatite6. Orthoclase7. Quartz8. Topaz9. Corundum (Ruby)10. DiamondCleavageThe tendency of a mineral to break along weak planes ofweak planes of bondingFracture Irregular breaking of a mineral Conchoidal fracture Splintery fractureSpecific gravity The ratio between the weight of a mineral and an equal volume of water of waterOther physical properties Magnetism Fluorescence Double refraction Double refractionTypes of Minerals 4000 have been named and about 40 to 50 are being named each year No more than a No more than a dozen are commonMineral Groups Silicates (SiO2, Mg2SiO4) Oxides (Fe2O3, Fe3O , Al O ) Carbonates(CaCO3,) Native elements(Au, Ag) Oxides (Fe2O3, Fe3O4, Al2O3) Sulfides (FeS2, ZnS) Sulfates (CaSO4, BaSO4) Native elements(Au, Ag) Halides (NaCl, CaF2) Hydroxides PhosphatesAbundance of elements in the Earths crust Oxygen Silicon Aluminum 46.6 % 27.7 % 8.1 % Aluminum Iron Calcium Sodium Potassium Magnesium 8.1 % 5.0 % 3.6 % 2.8 % 2.6 % 2.1 %Total =98.3Silicates Most abundant minerals on earth are silicates Building block is the Building block is the silicon tetrahedron SiO4-4Silicates Tetrahedrons can link Polymerization the linking of silicon tetrahedrons tetrahedronsIgneous rocksIgneous rock Definition: Rock formed from the crystallization of magma Composed of aggregates of interlocking Composed of aggregates of interlocking crystalline mineralsComposition of magma Dominantly ions of Silicon tetrahedra (SiO4-4) and cations (e.g. Fe+2, Fe+3, Mg+2) moving about in a hot liquid medium. moving about in a hot liquid medium.Composition of igneous rock Dominantly silicate minerals mineralsTypes of Igneous rocks Extrusive (volcanic rock) Intrusive (plutonic rock)Igneous textures Texture a term used to describe the overall appearance of the rock based on the size, shape, and appearance of thesize, shape, and appearance of the interlocking crystals Texture is important because it can be used to distinguish between an intrusive rock and an extrusive rockIgneous textures1. Phaneritic2. Aphanitic 3. Glassy3. Glassy 4. PorphyriticPhaneritic Coarse-grained texture with crystals large enough to be seen by the nakedseen by the naked eye (> 1 mm).Aphanitic Fine-grained texture with crystals not large enough to be seen by the nakedseen by the naked eye (< 1 mm)Glassy No crystals (minerals) are formed Unordered ionsPorphyritic Coarse-grained crystals inset in a finer-grained matrixFactors affecting size of crystals Rate of cooling Slowrate of cooling large crystals crystals Fast rate of cooling small crystals Very fast rate of cooling glassPorphyriticQ:Where did this porphyritic igneous rock form?A:First at depths of ~10 km from the surface and then was extruded along with the earlier formed minerals.PorphyriticQ:Where did this porphyritic igneous rock form?A:First at depths of ~10-20 km from the surface and was emplaced as an intrusive a few km below the surface of the earth.Heat source why rocks melt1. Geothermal gradient2. Decay of radioactive isotopesWhere rocks melt Below oceanic ridges At subduction zonesWhat are rocks that melt Oceanic crust (Basalt) and parts of the upper mantle (Peridotite) Continental crust (Granite) and parts of the upper mantle (Peridotite) (Peridotite)Crystallization of melts Bowens reaction series The relationship between magma and the minerals crystallizing from it during the formation ofcrystallizing from it during the formation of igneous rocks N.L. Bowen Some ions prefer to crystallize earlier than others There occurs selectivedepletion of ions in thedepletion of ions in the liquid magma (circles, triangles, and squares represent ions)Bowens reaction seriesGraniteDioriteBiotiteMuscoviteQuartzNa-rich plagioclaseRhyoliteLow-temperatureDioriteGabbroPeridotiteOlivinePyroxeneAmphiboleCa-rich plagioclaseAndesiteBasaltHigh temperature