Minerals

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Minerals
Chapter 2Earth MaterialsMinerals and Rocks
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Earth Materials Minerals

• Minerals are the basic units that make up most of
  Earths inorganic materials
• Minerals have many essential uses Can you name a
  few?

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What is a mineral?
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What is a mineral?

• 1. It is formed naturally

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What is a mineral?

• 1. It is formed naturally
• 2. It has a crystalline structure

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What is a mineral?

• 1. It is formed naturally
• 2. It has a crystalline structure
• 3. It is solid

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What is a mineral?

• 1. It is formed naturally
• 2. It has a crystalline structure
• 3. It is solid
• 4. It has a narrowly defined chemical
  composition

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What is a mineral?

• 1. It is formed naturally
• 2. It has a crystalline structure
• 3. It is solid
• 4. It has a narrowly defined chemical
  composition
• 5. It has characteristic physical properties

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What is a mineral?

• 1. It is formed naturally
• 2. It has a crystalline structure
• 3. It is solid
• 4. It has a narrowly defined chemical
  composition
• 5. It has characteristic physical properties
• 6. It is inorganic -- never living

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Minerals

• Chemical composition
• composed of elementsQuartz SiO2composed of
  one silicon atom and two oxygen atoms
• Distinct Properties color, luster, hardness,
  breakage, streak, taste, odor, magnetic, surface
  features, reactive with acid

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Matter and Its Composition

• Every substance on earth is composed of matter
• Matter has mass and volume
• (occupies space) solid, liquid, gas composed of
  elements
• Elements are chemical substances
• cannot be broken down chemically
• composed of atoms

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Atoms

• smallest particle that retains the nature of the
  element
• Nucleus contains particles
• protons neutrons no charge
• Electrons travel around the nucleus
• electrons --

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Structure of an Atom

• The dense nucleus of an atom
• consisting of protons and neutrons
• is surrounded by a cloud of orbiting electrons

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Particles in nucleus

• Atomic number the number of protonsThis
  determines the name of the element.
• Atomic mass number is the
• number of protons number of neutrons
• The number of neutrons in an atom
• may vary without changing the name of the element

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When neutrons vary

• Isotopes of the same element are formedIsotopes
  have the same atomic number
• Isotopes have different atomic mass numbers
• Isotopes of the same element behave the same
  chemically
• Isotopes are important in
• radiometric dating

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Carbon Isotopes

• Carbon atoms (with 6 protons)
• have 6 neutrons Carbon 12 (12C)

• have 7 neutrons Carbon 13 (13C)

• or have 8 neutrons Carbon 14 (14C)

• thereby making up three isotopes of carbon.

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Bonding and Compounds

• Bonding atoms join to other atoms
• Compound bonding of two or more elements
• Oxygen gas (O2) is an element
• Ice (H2O) is a compound
• Most minerals are compounds

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Atomic Bonding

• Ionic bonds electrons are donated or received

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Atomic Bonding

• Common types of bonding among atoms to form
  minerals
• Ionic bonds electrons are donated or received

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Atomic Bonding

• Common types of bonding among atoms to form
  minerals
• Ionic bonds electrons are donated or received
• Covalent bonds electrons are shared

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Atomic Bonding

• Common types of bonding among atoms to form
  minerals
• Ionic bonds electrons are donated or received
• Covalent bonds electrons are shared
• Metallic bonds electrons are located in a
  cloud around nucleus

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Atomic Bonding

• Common types of bonding among atoms to form
  minerals
• Ionic bonds electrons are donated or received
• Covalent bonds electrons are shared
• Metallic bonds electrons are located in a
  cloud around nucleus
• Vanderwaals bonds atoms are weakly attracted

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Ionic Bonding

• Ion atom that has gained or lost one or more
  electrons It has a negative or positive charge
• Ionic bonding
• attraction between two ions of opposite charge
• Goal atoms are more stable when outer electron
  shell is filled.

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Ionic Bonding
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halite
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Covalent Bonding

• Covalent bonding
• results from sharing electrons

shared electrons
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Metallic Bonding

• Electrons are loosely arranged in a cloud-like
  arrangement.
• Metals have properties of being good electrical
  conductors
• Metals are malleable

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MineralsThe Building Blocks of Rocks
Quartz consists of 1 silicon atom for every 2
oxygen atoms
Quartz SiO2 Ratio 1 2

• Potassium Feldsparconsists of 1 potassium, 1
  aluminum, and 3 silicon for every 8 oxygen atoms

KAlSi3O8 1 1 3 8
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Native Elements

• consist of only one element.
• They are not compounds.

gold formula Au
diamond formula C
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Allotropes of carbon polymorphs
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Mineral Properties

• controlled by internal arrangement of atoms
• Chemical composition
• Crystalline structure

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Color how reliable is color to identify a
mineral?

• Many varieties of quartz

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Crystal form

• If given enough room to grow freely
• minerals form perfect crystals with
• planar surfaces, called crystal faces
• sharp corners
• straight edges

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Mohs Scale of hardnessarranged from 1 to 10

• Hardness is a minerals resistance to abrasion or
  being scratched

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Streak testcolor of a mineral in its powdered
form
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Breakage yes, they all break, but some break in
predictable patterns

• Irregular breakage or fracturerandom, smooth,
  round (conchoidal) with no geometric shape or
  parallel flat sides

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Breakage

• Cleavage
• tendency to break in flat surfaces that are
  parallel may have one, two, three, even four
  pairs of flat sides, or planes.

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Types of mineral cleavage
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Surface feature - feldspars

• Exsolution LamellaePotassium Feldspar

• StriationsPlagioclase Feldspar

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Unique taste, odorhalite and sulfur
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Reaction with dilute hydrochloric acid
carbonate minerals
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Common rock forming minerals
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Rock-Forming Minerals

• Most rocks are solid aggregates of one or more
  minerals
• Thousands of minerals occur in rocks,
• but most rocks have common rock-forming minerals
• Most rock-forming minerals are silicates,
• but other groups are important

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Silicates

• Silicates are minerals containing silica
• Si and O
• They make up perhaps 95 of Earths crust
• and account for about 1/3 of all known minerals

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• The basic building block of silicates
• is the silicon oxygen tetrahedron
• which consists of one silicon atom
• surrounded by four oxygen atoms

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Earths crustelements by weight
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Types of Silicates

• Silica tetrahedra can be
• isolated units bonded to other elements
• arranged in chains (single or double)
• arranged in sheets
• arranged in complex 3D networks

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Types of Silicates

• Ferromagnesian silicates (dark)
• contain iron (Fe), magnesium (Mg), or both
• olivine, pyroxene, amphibole, biotite
• Nonferromagnesian silicates (light)contain
  potassium (K), sodium (Na), (Ca)calcium
• Quartz, muscovite, feldspar

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Ferromagnesian Silicates

• Common ferromagnesian silicates include

Pyroxene-
olivine
biotite mica
amphibole
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Nonferromagnesian Silicates

• Quartz Potassium feldspar
• Plagioclase feldspar Muscovite

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Other Mineral Groups

• Carbonates contain carbonate ion CO3 (CaCO3)
  calciteOxides (Fe2O3) MagnetiteHalides (
  NaCl) HaliteSulfides (PbS) Galena
•