Atoms to Minerals

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Atoms to Minerals

• Chapter 5

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5.1 Matter and Atoms

• Matter-
• Mass-
• Does mass ever change?
• Volume
• Matter is made up of elements which are in turn
  made up of atoms
• Structure of an Atom
• Mostly empty space (know football field and golf
  ball illustration)
• Nucleus-
• Protons
• The atomic number is the number of protons
• Neutrons
• examples
• Electron cloud
• Divided into levels with a different number of
  electrons possible per level

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5.1 Matter and Atoms

• Classifying atoms
• Found on the periodic table
• Organized by properties and their atomic number
• 92 natural elements, rest are synthetic
• Atomic number
• Atomic mass
• Isotopes
• Mass number
• Carbon 14 and carbon 12
• Name and symbol

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5.1 Matter and Atoms

• Compound-
• Bonding of atoms
• Covalent bonds-
• Ionic bonds-
• Ion
• Metal
• Non-metal
• Metallic bonds
• Mixtures-
• examples

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5.2 Composition and Structure of Minerals

• What is a mineral?
• Characteristics
• It occurs naturally
• It is solid
• It has a definite chemical composition
• Its atoms are arranged in an orderly pattern
• It is inorganic (it was never alive)
• There are 4000 known minerals
• Examples gold, quartz, halite, diamond
• 8 elements make up 98 of the crust
• These 8 elements form the compounds that make up
  minerals
• Quartz-siliconoxygen, galena- leadsulfur
• A few minerals are made of a single element
  (native elements)
• Silver, gold, copper, sulfure
• Mixtures of minerals are called rocks

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5.2 Composition and Structure of Minerals

• How minerals form?
• Magma process
• Magma rises and cools
• If magma cools rapidly the minerals will have
  small grains, if it cools slowly, the minerals
  will have large grains
• Atoms and ions move closer to one another
• Compounds and mixtures come together to form
  mineral types
• Pressure process
• High pressure and heat makes existing minerals
  and rocks break down
• Atoms, ions, and molecules reform in new ways to
  form new mineral types
• Evaporation process
• The evaporation of water leaves behind sediments
  that are minerals (halite)

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5.2 Composition and Structure of Minerals

• Structure of Minerals
• Crystal structure
• Crystal- a regular geometric solid with smooth
  faces
• The crystal shape is determined by how the atoms
  bond to one another
• Crystal types
• Cubic
• Orthombic
• Tetragonal
• Triclinic
• Hexagonal
• monoclinic

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5.2 Composition and Structure of Minerals

• Silicates-minerals that contain silicon and
  oxygen
• 90 of the minerals in the earths crust
• Basic building block is a silicon atom with four
  oxygen atoms around it
• Crystal structure and physical properties
• The conditions (heat and pressure) determine the
  following properites
• Cleavage the tendency to split along certain
  planes (see p. 101)
• Hardness- example graphite and diamonds
• Density
• Read Geodesic domes p. 103

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5.3 Identifying Minerals

• Mineralogy- the study of minerals and their
  properties
• Rock forming minerals
• Only a few minerals are present in most rocks
• Quartz, feldspar, mica, and calcite
• Identification of these minerals is done by
  various tests
• Identifying Minerals by Inspection
• Color
• Good for some minerals, not so good for others
• cinnabar-red, malachite-green, quartz-?????
• Luster- the way a mineral shines in reflected
  light
• Metallic
• Non-metallic
• Vitreous, pearly, greasy, oily, dull, earthy
• Crystal shape
• You need big enough crystals to see it

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5.3 Identifying Minerals

• Testing mineral specimens
• Streak
• Can change from its color
• Cleavage
• Fracture
• Hardness
• Mohs hardness scale (see p. 106)
• Specific gravity
• Chemical tests
• Special properties of minerals
• Double refraction
• Taste
• Magnetism
• radiation

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5.4 Mineral Groups

• Major silicates (90 of all minerals)
• List the most important characteristics for each
  one of these minerals
• Quartz
• Feldspars
• Pyroxenes
• Mica
• Amphibole
• Olivine
• Kaolinite

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5.4 Mineral Groups

• Carbonates
• List the most important characteristics for each
  one of these minerals
• Calcite
• dolomite

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5.4 Mineral Groups

• Oxides and Sulfides (have oxygen and sulfur)
• List the most important characteristics for each
  one of these minerals
• Hematite
• Magnetite
• Pyrite