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AtomsAtoms
Atoms – basic building blocks for all earth Atoms – basic building blocks for all earth materials; consist of 3 basic components: materials; consist of 3 basic components: protons, neutrons, electronsprotons, neutrons, electrons
Atoms combine to form Atoms combine to form ElementsElements
ElementsElements – fundamental component that – fundamental component that can not be broken down into other can not be broken down into other substances by ordinary chemical substances by ordinary chemical processesprocesses
Elements combine to form mineralsElements combine to form minerals
General Facts About MineralsGeneral Facts About Minerals
2,000 + minerals have been identified2,000 + minerals have been identified
A few are “native elements” -- made of A few are “native elements” -- made of only one element, such as sulfur, gold. only one element, such as sulfur, gold. copper, and graphite (carbon)copper, and graphite (carbon)
Most are compounds, especially the Most are compounds, especially the silicate group (Si, O).silicate group (Si, O).
Other important groups are oxides, Other important groups are oxides, carbonates, and sulfides.carbonates, and sulfides.
Gold (Au)Silver (Ag)Platinum (Pt)Diamond (C)Graphite (C)Sulfur (S)Copper (Cu)
MINERALS
NATIVE ELEMENTS
Copper
Silver
Gold
Mineral CriteriaMineral Criteria
1. Crystalline solid1. Crystalline solid2.2. Naturally occurringNaturally occurring3.3. Have a definite chemical compositionHave a definite chemical composition4. Inorganic4. Inorganic
Minerals are identified by their Minerals are identified by their Physical Properties Physical Properties
Crystal FormCrystal FormColorColorStreakStreakLuster – metallic, non-metallic Luster – metallic, non-metallic Hardness – Moh’s Hardness Scale (1-10)Hardness – Moh’s Hardness Scale (1-10)CleavageCleavageFractureFractureSpecific Gravity Specific Gravity OthersOthers
A mineral’s physical properties A mineral’s physical properties are controlled by its are controlled by its internal internal
arrangement of atomsarrangement of atoms
regularly repeating, orderly patternregularly repeating, orderly pattern
The most common crystalline The most common crystalline structure structure
Silica-oxygen tetrahedronSilica-oxygen tetrahedron – basic – basic building block for silicate mineralsbuilding block for silicate minerals
Silica tetrahedron combine Silica tetrahedron combine several different waysseveral different ways
Five major types of Five major types of silicate minerals silicate minerals based on their based on their structurestructure
A)A) Isolated tetrahedronIsolated tetrahedron
B)B) Single chainSingle chain
C) Double chainsC) Double chains
D) Sheet silicates D) Sheet silicates
E) 3-D framework E) 3-D framework silicatessilicates
Minerals can have the same chemical composition Minerals can have the same chemical composition (Carbon) but different physical properties because (Carbon) but different physical properties because
of their crystal structureof their crystal structure
Diamond GraphiteDiamond Graphite
COLORCOLOR
Color is not usually a definitive property of Color is not usually a definitive property of a mineral. a mineral.
Some minerals have characteristics colorsSome minerals have characteristics colorsOthers vary due to chemical differences or Others vary due to chemical differences or
impurities (atoms mixed inside the main impurities (atoms mixed inside the main elements)elements)
However most minerals have a variety of However most minerals have a variety of colorscolors..
STREAKSTREAK
For opaque minerals, if you rub the For opaque minerals, if you rub the sample across a streak plate, it will leave a sample across a streak plate, it will leave a colored powder. This streak is distinctive colored powder. This streak is distinctive for minerals and is used to identify for minerals and is used to identify minerals. minerals.
HARDNESS – Mineral’s resistance to HARDNESS – Mineral’s resistance to scratching. Minerals with higher numbers scratching. Minerals with higher numbers
will scratch minerals belowwill scratch minerals below
LUSTERLUSTER
Describes how light reflects off the surface Describes how light reflects off the surface
Categories: Metallic or non-metallicCategories: Metallic or non-metallic
Metallic does not mean shinyMetallic does not mean shiny
Non-metallic: vitreous or glassy; silky; Non-metallic: vitreous or glassy; silky; resinous; pearly; greasy; waxy, dull; earthyresinous; pearly; greasy; waxy, dull; earthy
Example of non-metallic lusterExample of non-metallic luster
Silky--example plagioclase feldsparSilky--example plagioclase feldspar
Non-metallic and metallic luster – Non-metallic and metallic luster – earthy hematite – metallic hematiteearthy hematite – metallic hematite
Cleavage and FractureCleavage and Fracture
Some minerals split along flat surfaces Some minerals split along flat surfaces when struck hard--this is called mineral when struck hard--this is called mineral cleavagecleavage
Other minerals break unevenly along Other minerals break unevenly along rough or curved surfaces--this is called rough or curved surfaces--this is called fracture fracture
A few minerals have both cleavage and A few minerals have both cleavage and fracture ( mica )fracture ( mica )
DENSITY / SPECIFIC GRAVITY DENSITY / SPECIFIC GRAVITY
This is the ratio of the density of the This is the ratio of the density of the mineral to the density of water. mineral to the density of water.
Weight Air/(Weight Air-Weight in water) = Weight Air/(Weight Air-Weight in water) = specific gravityspecific gravity
Acid Test for CarbonatesAcid Test for Carbonates
Special Characteristics:Special Characteristics:
Carbonates react with dilute HCl and other Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing acids by fizzing or bubbling (releasing CO2 gas)CO2 gas)
MINERALSNONSILICATE MINERALSCARBONATES
Carbonate ion (CO32-) is prominent in minerals.
Has -2 charge.Combines readily with positive ions.Bonds generally weak.Minerals are soft (3-4).Minerals are soluble in acidic water.
Leads to cave development.
Calcite (CaCO3)Dolomite (CaMg(CO3)2)
DOLOMITE
CALCITE
Less than a dozen are common in Less than a dozen are common in most rocksmost rocks
QuartzQuartz Feldspar (group)Feldspar (group) Muscovite (silver white mica)Muscovite (silver white mica) Biotite (black mica)Biotite (black mica) CalciteCalcite PyroxenePyroxene OlivineOlivine Amphibole (group)Amphibole (group) Magnetite, limonite, and other iron oxidesMagnetite, limonite, and other iron oxides PyritePyrite
Common uses include:Common uses include:
Aluminum--packaging, transport, buildingAluminum--packaging, transport, building Beryllium--gemstones, fluorescent lightsBeryllium--gemstones, fluorescent lights Copper--electric cables, wires, switchesCopper--electric cables, wires, switches Feldspar--glass and ceramicsFeldspar--glass and ceramics Iron--buildings, automobiles, magnetsIron--buildings, automobiles, magnets Calcite--toothpaste, constructionCalcite--toothpaste, construction