Geo 101N 4th Edition Lecture 11Outline of Last Lecture I. What are minerals?II. Mineral status requirementsIII. Crystalline StructureIV. Formation/Destruction of MineralsV.GemsVI. Inside MineralsOutline of Current Lecture VII. Mineral CharacteristicsVIII. Mineral ClassesIX. Common Rock-forming MineralsX. RocksXI. Rock ClassificationXII. Physical CharacteristicsCurrent LectureIV. Mineral Characteristicsa. Facets: smooth reflective surfaces produced by grinding and polishingb. Silicates: most abundant class of minerals in Earth’s crust and mantle-over 95% ofcontinental crust &almost 100% ofoceanic crust- SiO4 anionicgroup→ silicatetrahedronc. Quartz: 6-sidedcrystals thatterminate at apointThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.d. Calcite: forms rhombohedral crystals w/sides that are NOT @ 90ᵒ to one anothere. Prime characteristics: that geologists use to separate minerals into classes is chemicalcomposition, specifically the anions w/in the chemical formulaf. Streak: color of the powder when pulverizedg. Luster: way the surface scatters lighth. Hardness: ability to resist scratching (Mohs hardness scale)i. Specific gravity: density of a mineral; ratio between the weight of the mineral and an equal volume of waterj. Crystal habit: shape of a single crystal with well-formed facesk. Color: way it interacts with light, caused by impuritiesl. Cleavage: tendency to break along internal planes of weakness-produces shiny flat surfaces-described by the # of planes & their angles-1,2,3,4 & 6 cleavage directions possiblem. Fracturen.o. Conchoidal fracture (like what happens to your windshield)V. Mineral Classesa. Silicates: see aboveb. Oxides: metal cations bonded to O anions (ie hematite Fe2O3); contain lots of oresc. Sulfides: a metal cation bonded to a sulfide anions (S, ie Pyrite)d. Sulfates: a metal cation bonded to a sulfate; many precipitate out of seawater (ie gypsum)e. Halides: halite or salts (NaCl or fluorite CaF2)f. Carbonates: CO3 g. Native metals: pure masses of a single metalVI. Common Rock-forming Mineralsa. Felsic: Fel=feldspar; sic=silicate -feldspar; most common crustal mineral; contains SiO4 w/either Al or Si substitutes, also contains Na, K and/or Ca b. Mafic: Ma=magnesium; fic=iron: Fe/Mg containing silicates-olivine, pyroxene and a third one I missedVII. Rocksa. Rock: a coherent (rock that holds together), naturally occurring solid, consisting of an aggregate of minerals or (less common) glassb. Cement: mineral material that precipitates from water & fills the space between grains = clastic rocks are held together by cementVIII. Rock Classificationa. igneous: formed by the freezing (solidification) of molten rockb. sedimentary: cementing together of fragments (grains) off existing rocks or by the precipitation of mineral crystals out of waterc. metamorphic: form from preexisting rocks change character in response to change in pressure and/or temperature conditionsIV. Physical Characteristicsa. Grain size: equant: same dimensions in all directionsInequant: the dimensions are not the same in all directions-sometimes grains are all the same size, in others they are notb. Composition: the proportions of different chemicals making up the rockc. Texture: the way grains connect to one another & whether or not inequant grains are aligned parallel to each otherd. Layering: defined either by bands of different composition or