Minerals

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Minerals

• the building blocks of rocks
• Pictures of minerals taken from
• http//www.minerals.net/mineral/sort-met.hod/color
  /color.htm
• http//www.minerant.org/images.html

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Minerals

• A Mineral.
• is naturally occuring
• is inorganic
• is solid
• has an orderly atomic structure
• has a definite chemical composition

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Minerals vs. Rocks

• A Rock is.
• any solid mass
• of minerals or mineral-like matter
• that occurs naturally

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Properties of Minerals

• Crystal Form
• Represents the internal arrangement of atoms

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Properties of Minerals

• Crystal Form
• Represents the internal arrangement of atoms
• Crystals may sometimes grow quite large

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Properties of Minerals

• Crystal Form
• Represents the internal arrangement of atoms
• Crystals may sometimes grow quite large
• Usually they are small and/or intergrown

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Properties of Minerals

• Luster
• describes the appearance of a mineral
• ex. metallic
• silky
• waxy
• dull
• vitreous

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Properties of Minerals

• Color
• not a good property to use to identify a mineral!

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Properties of Minerals

• Streak
• the color of the mineral in its powdered form

• from http//geology.csupomona.edu/alert/mineral/st
  reak.htm

from http//lewis.up.edu/mcs/wasowski/sci110/TnTkC
h02/sld026.htm
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Properties of Minerals

• Hardness
• the resistance of a mineral to being
  scratched
• Mohs Scale of Hardness (1-10)
• 1 talc, 2 gypsum, 7 quartz, 10 diamond
• 2.5 fingernail, 3 penny, 5.5 glass

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Properties of Minerals

• Cleavage
• Cleavage is the tendency for a mineral to break
  along a flat surface.
• Cleavage ? Crystal form!!!
• Minerals that do not exhibit cleavage are said to
  fracture.
• ex. Quartz conchoidal fracture

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Properties of Minerals

• Other Properties
• taste (Halite)
• reaction with hydrochloric acid (Calcite)
• magnetism (Magnetite)
• double refraction (Calcite Iceland Spar)

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Mineral Groups

• 4000 named minerals!
• but only a few dozen are abundant
• Most common mineral group Silicates
• Other important minerals -
• carbonate group
• native elements
• other important ores and economic resources

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Silicate Minerals

• Contain silicon and oxygen
• building block SiO4
• silica tetrahedron

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Silicate Minerals

• Silicate minerals can form many ways.
• some form when magma cools and crystallizes
• some form when other minerals react with water
  and gases in the atmosphere
• still others form during metamorphism

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Silicate Minerals

• Dark Silicate Minerals
• ferromagnesian silicates
• the dark color indicates the presence of iron
  and/or magnesium in the crystal lattice
• Light Silicate Minerals
• nonferromangesian silicates
• the light color indicates the lack of iron and/or
  magnesium in the crystal lattice

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Silicate Minerals

• Silicates are grouped according to how the
  tetrahedra are linked together
• chains, sheets, or a 3-d network
• Bonds between tetrahedra are very strong!
• Cleavage planes will not form across Si-O bonds!

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Silicate Minerals

• Tetrahedra may form chains
• Bonds between tetrahedra are very strong
• cleavage planes exist between chains, not
  across them
• - minerals tend to form long prismatic crystals

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Silicate Minerals

• Tetrahedra may form sheets
• Bonds between tetrahedra are very strong
• cleavage planes exist between sheets, not
  across them

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Silicate Minerals

• Tetrahedra may form a 3-dimensional
  network
• Bonds between tetrahedra are very strong
• - if other ions are in the mineral, 2-planes of
  cleavage exist
• if pure Si O, cleavage planes do not exist!

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Carbonate Minerals

• Contain carbonate ions (CO3-)
• Extremely important in sedimentary rocks!!
• Calcite

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Important Mineral Resources

• Native Elements
• gold, silver, copper, etc.
• Important Ores
• magnetite hematite (iron ores)
• galena (lead ore)
• Important Economic Minerals
• gypsum (wallboard and plaster)
• calcite (cement)
• halite (salt)
• Gemstones

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Unit 2 Test Next Class

• Properties of Minerals
• Silicate Minerals
• Carbonates, Other Mineral Resources, Specific
  Mineral Properties (lab related)
• 20 multiple choice (1 point each)
• 10 point essay on cleavage in silicate minerals

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Geopardy
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Properties of Minerals - 100

• Define streak.
• The color of a mineral in its powdered form.

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Properties of Minerals - 200

• Define cleavage
• The tendency of a mineral to break along flat
  parallel surfaces.

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Properties of Minerals - 300

• Give both mineral 1 and 10 on Mohs Scale of
  Hardness
• 1 talc 10 diamond

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Properties of Minerals - 400

• Give two reasons why color is not a very good
  property upon which to base a mineral
  identification.
• Different samples of the same mineral may have
  different colors, and samples of different
  minerals may have the same color.

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Properties of Minerals - 500

• Give all five parts of the definition of Mineral
  (as presented in class).
• A mineral is a naturally occurring, inorganic,
  solid material. It has an orderly atomic
  structure and a definite chemical composition.

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More Properties of Minerals - 100

• What is the luster of a mineral?
• Luster describes the way a mineral sample
  reflects light.

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More Properties of Minerals - 200

• What does vitreous mean?
• Glassy, or glass-like

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More Properties of Minerals - 300

• This property of minerals represents the internal
  arrangement of atoms.
• Crystal Form

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More Properties of Minerals - 400

• A mineral that breaks along curved surfaces is
  said to have what?
• Conchoidal fracture

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More Properties of Minerals - 500

• How is a mineral different from a rock? (Be very
  specific!)
• A rock does not have to have an orderly atomic
  structure. It does not have to have a definite
  chemical composition. A rock may also be
  organically formed.

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Silicates - 100

• What is the name of the building block of
  silicate minerals?
• Silica tetrahedron

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Silicates - 200

• What is the chemical formula of the building
  block of silicate minerals?
• SiO4

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Silicates - 300

• What are dark-colored silicate minerals also
  known as?
• Ferromagnesian silicates

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Silicates - 400

• What does it mean when a silicate mineral has a
  dark color?
• Iron and/or magnesium is present in the crystal
  lattice of the mineral.

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Silicates - 500

• Explain the connection between the arrangement of
  silica tetrahedra in a silicate mineral and the
  formation of cleavage of the mineral.
• No answer will be printed below!

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Other Minerals - 100

• What mineral group is especially important in the
  formation of sedimentary rocks?
• The Carbonate Group

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Other Minerals - 200

• Give three examples of native elements.
• The three most commonly thought of are gold,
  silver, and copper, but there are others.

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Other Minerals - 300

• What is the chemical composition of the ion found
  in carbonate minerals?
• Carbonate ion CO3-

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Other Minerals - 400

• Give two examples of minerals that are important
  ores.
• Some examples include hematite (iron ore), galena
  (lead ore), and magnetite (iron ore), but there
  are many others.

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Other Minerals - 500

• Give two examples of important economic minerals
  (that are not ore minerals)
• Examples include gypsum (used in plaster and
  wallboard), calcite (used in cement), salt (used
  as salt), but there are many others.

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Random Mineral Facts - 100

• This mineral with a metallic luster is also known
  as fools gold.
• Pyrite

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Random Mineral Facts - 200

• This mineral was once used instead of glass in
  windows in Russia.
• Muscovite

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Random Mineral Facts - 300

• This mineral reacts with hydrochloric acid and
  has double refraction.
• Calcite

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Random Mineral Facts - 400

• This is the state mineral of California.
• Benitoite

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Random Mineral Facts - 500

• This mineral (in its finely granular, powdered
  form) helps to give Mars its red appearance.
• Hematite

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