Download MINERALS

MINERALS

Chemical composition of the Crust  

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Oxygen most abundant- 46.6% Followed by silicon and aluminum Iron, Calcium, Sodium, Potassium, Magnesium The most common minerals will be composed mostly of these elements Silica & silicates

MINERAL vs. ROCK 

ROCK  An

aggregate of one or more MINERALS (usually- coal, organic)

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MINERAL  Solid  Crystalline-

orderly arrangement of atoms  Naturally occurring  Inorganic  Definite chemical composition  e.g.

SiO2 for quartz; KAlSi3O8 for feldspar

Atom & Elements 

Atoms  Neutral  Nucleus  Proton,

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Electron

Ions  Electrical

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neutron

Charge

Molecule- e.g. water molecule

Chemical activity 

Stable atoms want  positive

& negative charges balanced  electron shells full  

Ions- positive (Cations) and negative (Anions) Bonding  Ionic  Covalent  Metallic  Van

der Waal’s

Element 

Atomic number  Number

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of PROTONS

Isotope  Differing

number of NEUTRONS

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Atomic weight  Mass

of PROTONS and NEUTRONS

Crystallinity  

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3 dimensional orderliness of atoms Silicon-oxygen tetrahedron Silicate structures  Single-

e.g. olivine

 Chain  Single

chain- pyroxene  Double chain- amphibole  Sheet-

e.g. mica, clay  Framework- e.g. quartz, feldspar

MINERALS   

Crystalline solids Natural and Inorganic Substances Definite chemical composition  Can

be written as a chemical formula  Solid solution (within a range)

Important Minerals  

Quartz (most abundant) FELDSPAR Group  Potassium

Feldspar - Orthoclase  Plagioclase Feldspar  Sodium

(Na) Albite  Calcium (Ca) Anorthosite

Important Minerals 

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PYROXENE Group- Augite most common AMPHIBOLE Group- Hornblende most common MICA Group- Si + O in sheets  Biotite  Muscovite

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CALCITE- CaCO3

Properties of Minerals 

Color  Not

always reliable (Olivine, green; Flourite, yellow, purple, green…)  Ferromagnesian minerals green or black  

Streak- powdered form Luster- reflectance of light  Metallic  Nonmetallic  Vitreous  Earthy

or Glassy

Properties of Minerals  

Hardness- resistance to scratching Moh’s Hardness Scale  Fingernail

= 2.5  Penny = 3.5  Knife/Glass = 5.5  Streak Plate= 6.5

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Cleavage

Properties of Minerals

 Quality

(poor, good, perfect)  Number of directions  One-

e.g. Mica  Two at right angles- e.g. Feldspar, Pyroxene  Two not at right angles- e.g. Amphibole  Three at right angles (cubic)- e.g. Halite  Three not at right angles (rhombohedral)- e.g. calcite  Four (Flourite) or six (Sphalerite)- not common

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Properties of Minerals

Fracture  Absence

of cleavage  Irregular fracture  Conchoidal fracture- Quartz 

Density  Specific

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Gravity

Some unusual properties  Striations,

refraction

Magnetism, Taste, Odor, Double

Chemical tests 

Reaction with HCl  Calcite

effervesces

Mineral Groups    

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Silicates Carbonates Oxides Sulfides Sulfates Native Elements Halides

Silicates  

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Quartz Feldspar  Plagioclase  Orthoclase Micas  Muscovite  Biotite Amphibole (Hornblende) Pyroxene (Augite) Olivine

Carbonates  

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Calcite (calcium carbonate) Dolomite (calcium-magnesium carbonate) Both are used as Portland Cement

Oxides 

Hematite (iron oxide)  Iron

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Magnetite  Iron

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ore, pigment ore

Corundum (aluminum oxide)  Sapphire,  Abrasive

ruby (gemstone)

Sulfides 

Galena (Lead sulfide)  Lead

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Sphalerite Zinc sulfide)  Zinc

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ore

ore

Pyrite (Iron sulfide)  Sulfuric

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acid

Chalcopyrite (Copper Iron sulfide)  Copper

ore

Sulfates   

Gypsum Anhydrite Both use in plaster

Native Elements     

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Gold- trade, instruments Silver- photography, conductors Copper- electrical Platinum- catalysts Sulfur- chemicals, pharmaceuticals Diamond- carbon  Gemstone, abrasive Graphite- carbon  Lubricant, pencils

Minerals as Resources 

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Reserves: Minerals that can be extracted at a profit under current economic and technological conditions Ores: metallic minerals Industrial Rocks or Minerals: non metallic minerals (phosphate) Aggregates: crushed rock

ROCK CYCLE  

Equilibrium Interrelationships between  igneous

rocks  sediment  sedimentary rocks  metamorphic rocks  weathering and erosion