Matter

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Atoms and Minerals
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Matter

• Matter has mass and volume
• Matter is found in 3 states solids, liquids,
  gases
• Matter is composed of elements, which are
  substances that cannot be broken down into other
  substances by ordinary chemical means
• There are 92 naturally occurring elements

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Atoms

• Elements are composed of tiny particles, atoms,
  which are the smallest units that have all the
  characteristics of a particular element

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Atoms

• In the center of an atom is the nucleus, which is
  composed of one or more particles protons (),
  neutrons (neutral)
• Electron shells surround the nucleus, and contain
  electrons (-)
• Atoms are held together by electrical attraction
  between positively charged protons in the nucleus
  and negatively charged electrons in the outer
  shells

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Atoms

• of protons atomic number, which is unique to
  each element
• Atoms of the same element may have varying
  numbers of neutrons, such atoms are called
  isotopes

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Bonding

• Electron shells innermost always 2 electrons,
  other shells up to 8 electrons
• Interaction of electrons between atoms controls
  bonding and creation of compounds

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Types of Bonding

• Ionic exchange of electrons between atoms to
  produce full outer shells (8)
• Example An atom of Cl and an atom of Na transfer
  one electron, leaving Cl negatively charged with
  one extra electron, and Na positively charged
  with one more proton than electron
• Charged particles are ions

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Na and Cl exchange electrons to become charged
ions and bond together to form Sodium Chloride,
also known as the mineral Halite, which is common
table salt
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Halite has a cubic crystal habit, which is a
physical reflection of how the Na and CL atoms
bond together
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Types of Bonding

• Covalent bonding in which atoms share electrons
  in their outermost shells

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Bonding

• Metallic electrons freely move from atom to atom
  producing unique properties such as malleability
  and electrical conductivity silver, gold,
  platinum
• van der Waals secondary residual attraction with
  no electrons involved

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Minerals

• Naturally occurring
• Inorganic
• Crystalline solid geometric shapes reflect the
  internal atomic arrangement
• Narrowly defined chemical composition (specific
  chemical formula)
• Characteristic physical properties

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Mineral composition

• Minerals are compounds formed by bonding of atoms
  of different elements
• Chemical formulas provide composition SiO2 one
  Si atom, two O atoms
• Olivine (Mg, Fe)2SiO4 - Mg and Fe are very
  similar in size and have equal charges so they
  can substitute for one another in this mineral

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Minerals

• 4000 known minerals
• Only 8 elements are very common in the crust
  combinations of these and other less common
  elements produce the 24 common crustal minerals

Mg K Na
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Mineral Groups

• Atoms commonly bond in tight complex groups known
  as radicals
• Radicals form the basis of mineral groups
• Minerals that are very abundant in the crust,
  such as quartz and calcite, also form the
  radicals for the two most common mineral groups,
  the silicates and the carbonates

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Mineral Groups Silicates

• Silicates minerals formed from Silica (SiO2)
  combined with other elements example Orthoclase
  KAlSi3O8
• The basic building block (radical) of silicates
  is the silica tetrahedron (Si04)-4, which can
  bond with positive ions singly, in chains, in
  sheets or in complex 3-D networks

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Silica Tetrahedron
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Mineral Groups Carbonates

• Carbonates based upon the carbonate radical
  (CO3)-2, example Calcite, CaCO3, which is the
  primary mineral in limestone

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Other Mineral Groups

• Oxides O other elements, ex. Hematite, Fe2O2
• Sulfides S other elements, ex. Galena, PbS
• Sulfates SO radical other minerals
• Halides Halogens (chlorine, florine) other
  minerals, ex. Halite (NaCl)

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Mineral identification

• Every mineral has characteristic physical
  properties identification is based upon analysis
  of these properties, which include
• Color- a mineral may be a variety of colors,
  which makes color a poor identifier
• Luster- refers to the way a mineral reflects
  light either metallic or non-metallic
• Non-metallic may be described as vitreous,
  greasy, waxy, dull, earthy, brilliant

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Mineral Identification

• Crystal form- reflects the way atoms fit together
  during bonding, often hidden due to limited
  growth space fluorite, cube calcite, elongate
  pyramid
• Cleavage- pattern of breakage along bonding
  planes, controlled by crystal geometry fluorite,
  4 cleavage planes calcite, 3 cleavage planes in
  a rhombohedron

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Mineral identification

• Hardness Mohs Scale

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Specific Gravity

• Specific gravity ratio of mass compared to
  equal volume of water
• Gold-19.3
• Galena-7.58
• Graphite-2.21

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Mineral Identification

• Refraction calcite double refraction
• Taste halite salty
• Magnetism Magnetite

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Mineral identification

• Chemical reactivity Calcite/HCL
• Streak color of powdered mineral on streak plate

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Chemical Reactivity Calcite
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Formation of Minerals

• Cooling of Magma\Lava
• Hydrothermal
• Evaporation
• Precipitation
• Metamorphism

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What is a Rock?

• Aggregates of minerals minerals are to a rock as
  bricks are to a wall!