Minerals Review

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Minerals (Review)

• Terms

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Mineral is

• Naturally Occurring--Not man made.
• Crystalline solids whose atoms are arranged in
  a regular repeating pattern.
• Inorganic Not derived form plants or animals.
• Specific chemical composition All minerals have
  a specific chemical composition within a specific
  range.

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Types of chemical bonds

• Ionic one atom gives away one or more electrons
  to another atom. The giving atom becomes a
  positive charged cation. The receiving atom
  becomes negatively charged anion. Since and
  attract each other these atoms become bonded or
  bound to each other. Example NaCl.

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Types of chemical bonds

• Covalent One atom shares some of its electrons
  with one or more other atoms.
• Example diamond is the covalent bonding of
  Carbon (C) atoms.
• H2O (though a non mineral) is a good example of
  covalent bonding. Oxygen has two empty slot in
  outer most energy level, and Hydrogen has one
  empty slot. To satisfy both they end up sharing
  electrons and a covalent bond results.

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Types of chemical bonds

• Metallic type of bonding found in metals.
  Electrons are loosely bond to any specific
  nucleus, and so can flow freely from one nucleus
  to the other. This is the reason that metals
  conduct electricity so well ( the electrons are
  so free to move.).

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Atoms

• Parts of an atom
• Protons--charged, relatively mass particles
• Number of protons in an atom determines what
  element it is, and is called the atomic number.
• Neutrons are neutral particles, having no
  charge. Similar to protons in size.
• Atoms with the same number of protons but
  different numbers of neutrons are isotopes of the
  same element.

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Atoms

• Parts of an atom continued
• Electrons-- negatively charged, extremely light
  particles 1850 e- make up the mass of one proton
  (approximate).
• Behavior of the electrons determines the chemical
  behavior of a given element.

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Other Atomic Terms Needed

• Ions An atom without the same number of
  electrons and protons resulting in the atom not
  being electrically neutral. There are two types.
• Cationsmore protons than electrons, charged.
• Anions more electrons than protons, - charged.

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Other Atomic Terms Needed

• Electron Shells electrons orbit the nucleus, but
  are restricted to discrete orbital distances from
  the nucleus called electron shells.
• Each electron shell can hold a specific number of
  electrons (2-8-18-32-32-18-8).
• If a given atom has a full outer elecron shell,
  that atom is highly stable and reacts only weakly
  with other atoms (Noble gases). All other atoms
  will either give away, gain or share electrons.

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Mineral Classes

• Based on the dominant chemical compound that
  makes up the mineral.
• SilicatesMade of SiO4, in combinations with
  various elements such as calcium, magnesium,
  iron, etc. The silicates are the most abundant
  mineral type in the crust.
• Silicate ions form tetrahedral crystals. These
  tetrahedral shapes can form various forms such as
  isolated tetrahedra (olivine), rings
  (cordierite), single chains (pyroxenes), double
  chains (amphiboles), sheets (micas), and
  frameworks (quartz).

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Mineral Classes

• Carbonates Made from the carbonate ion CO3, in
  combination with various other elements.
• Calcite is the common carbonate mineral, one form
  is aragonite (sea shells). There is also Calcite
  (CaCO3), and Dolomite ( CaMgCO3).
• Oxides Made from oxygen combined with other
  elements such as iron, titanium, ect. Many
  economically important metals are mined as oxide
  ores.

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Mineral Classes

• Sulfides Made of sulfur with other minerals such
  as copper, iron, zinc, etc. Many economically
  important metals are mined as sulfide deposits.
• Sulfates made from the sulfate ion (SO4)
  combined with minerals such as clacium, and
  barium. Gypsum is a sulfate mineral.

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Mineral Classes

• Halides salts of various kinds. NaCl is called
  halite, there are also KCl called Sylvite.
• Native metals metals such as Gold, silver,
  copper etc..
• Native elements such as sulfur, diamond,
  graphite, arsenic.

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Mineral Identification

• To identify minerals we use a variety of physical
  properties such as
• Hardness
• Cleavage
• Fracture
• Luster
• Color
• Streak
• Density
• Habit
• You need to know which each of these refer to and
  how it is used.

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Summary

• You should be able to do the following
• Define what a mineral is.
• Discuss the Atomic theory of matter (atoms,
  protons, neutrons, electrons, etc.)
• Know the types of chemical bonds in minerals
  (ionic, covalent, metallic) and how they work.
• Discuss the basics of crystallization (how it
  takes place).
• Know the different mineral classes.
• Know how the minerals are identified.

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SITES USED

• Thanks to Greg Anderson for use of lecture notes.
• http//pasadena.wr.usgs.gov/office/ganderson/es10/
  lectures