Geology 1303Block 2 Minerals Rock Cycle Igneous Rocksincluding volcanoes

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Geology 1303-Block 2MineralsRock
CycleIgneous Rocks-(including volcanoesplutons)
Sedimentary RocksMetamorphic rocksExam 2 Oct
18th WED -To be Confirmed
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• What is a mineral?
• How do we differentiate a mineral from a piece of
  wood or a human?
• What is a rock?

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Minerals

• What is a mineral?
• Naturally occurring (not man-made)
• Inorganic
• Solid (not made of liquid or gas) with a definite
  chemical structure which give it unique physical
  properties.

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Minerals vs. Rocks

• There are nearly 4000 known minerals - but most
  rocks are formed by only a few dozen minerals.
• Rocks are aggregates (mixtures) of minerals. So .
  . . minerals are the building blocks of rocks.
• A question for the future How do minerals come
  together to form a rock?

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Composition and Structure of Minerals

• To understand how minerals form, we need to
  understand the characteristics of elements and
  atoms.
• Chemical Elements
• Elements are the basic building blocks of
  minerals. There are over 100 known elements.

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Composition and Structure of Minerals

• Atoms
• smallest particle of matter that exhibits all the
  characteristics of an element.
• Atoms are made up of
• Nucleus, which contains Protons (atomic number)-
  positive electrical charges and Neutrons -
  neutral electrical charges (P N atomic mass)
• Shells which surround the nucleus and contain
  Electrons - negative electrical charges
• The weight (density) of an element depends on the
  number of protons and neutrons in the nucleus.

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Combining Elements to Form Minerals

• Elements combine with each other to form a wide
  variety of minerals (chemical compounds)
• Atoms combine chemically by gaining, losing, or
  sharing and electron with other atoms. (opposites
  attract) (pg-26)
• The new mineral (compound) will have very
  different physical properties from the elements
  that combined to form it.

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Combining Elements to Form Minerals

• Since rocks are mixtures (not chemical
  combinations) of minerals, minerals keep their
  physical properties within a rock.
• Is it possible for two different minerals to have
  the same chemical composition?
• YES! Both diamond and graphite are made of
  carbon. The difference between these two
  minerals is the way in which the carbon atoms are
  arranged.

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Mineral Properties

• Minerals have lots of different properties that
  help us identify them.
• Crystal form, Luster, Color,
• Streak, Hardness, Cleavage,
• Fracture, Specific gravity,
• Taste, Smell, etc.

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Rock Forming Minerals

• The most common rock forming minerals are
  composed of 8 elements
• Oxygen (O) , Silicon (Si),
• Aluminum (Al) , Calcium (Ca) , Sodium (Na) ,
  Potassium (K)
• Iron (Fe) and Magnesium (Mg)
• There are just a few dozen minerals that we call
  the rock-forming minerals.

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Composition of the Crust

• The most abundant elements in Earth's crust are
• Oxygen (46.6 by weight)
• Silicon (27.7 by weight)

The crust
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Silicate Minerals

• Silicate minerals, minerals built primarily from
  silicon-oxygen tetrahedrons, are the most common
  rock-forming minerals.
• Silicate minerals are grouped according to how
  the tetrahedrons are arranged in the mineral.

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Silicate Mineral Groups

• Olivine - independent tetrahedrons (Mg, Fe)
• Pyroxene group - tetrahedrons are arranged in
  chains (Mg, Fe)
• Amphibole group - tetrahedrons are arranged in
  double chains (Mg, Fe, Ca)
• Micas - Tetrahedrons are arranged in sheets
• Two common types of mica
• Biotite (dark) (K, Mg, Fe, Al),
• Muscovite (light) (K, Al)

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Silicate Mineral Groups

• Feldspars - Three-dimensional network of
  tetrahedron
• Two common types of feldspars
• Orthoclase (K, Al)
• Plagioclase (Ca, Na)
• Most plentiful mineral group
• Quartz - three-dimensional network of
  tetrahedrons (SiO2)

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Mineral Color

• Mineral color is often governed by presence of
  Mg, Fe (dark) or absence of these elements
  (light).

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Non-Silicate Minerals

• Major groups
• Oxides (FeO2), Sulfides (PbS), Sulfates (CaSO4),
• Halides,
• "Native" elements (gold),
• Carbonates (limestone, marble) (CaCO3)

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Mineral Resources

• Ore - rock that contains useful metallic minerals
  that can he mined at a profit.
• Since 98 of the Earth's crust is made up of 8
  elements, an element/mineral has to be
  concentrated at levels above normal for
  profitable mining.

Rocks
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A Rock is anAggregateof Minerals
Quartz
Amphibole
Feldspar
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Structureof an Atom
Electron
Nucleus
Nucleus (neutrons protons)
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Chemical Compound
Na
Cl-
NaCl
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Silicon-OxygenTetrahedron(SiO4)
Isolated Tetrahedrons (Olivine)
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Tetrahedron Arrangement
Single-Chain
Double-Chain
Sheet
Pyroxene
Amphibole
Mica
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Mohs hardness scale

• 10. Diamond 4. Fluorite
• 9. Corundum 3. Calcite
• 8. Topaz 2. Gypsum
• 7. Quartz 1. Talc
• 6. Potassium Feldspar
• 5. Apatite

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• Please do not use WebCT for email
• aellis_at_utep.edu
• Minerals Cont.
• Rocks and the Rock Cycle

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For Next Time

• How do minerals "mix" together to form rocks?
• What is the rock cycle ?