Chapter 4: Section1 What Are Minerals?

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Chapter 4 Section1What Are Minerals?

• Minerals a naturally occurring, inorganic solid
  that has a crystal structure and a definite
  chemical composition

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What 5 Characteristics Does a Mineral Have to
Have?

• A mineral must be
• Naturally Occurring
• Inorganic
• Solid
• Crystal Structure
• Definite Chemical Composition

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What Does It Mean to Be Naturally Occurring?

• A mineral must occur naturally
• Cement, brick, steel, and glass all come from
  substances found in Earths crust but they are
  manufactured by people

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How Can Something Be Inorganic?

• Inorganic the mineral cannot arise from
  materials that were once part of a living thing
• Ex. Coal is NOT a mineral because it is made up
  the remains of plants and animals

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What kind of pattern must a mineral have?

• A mineral must have a crystal structure a
  repeating pattern of a minerals particles that
  forms a solid.
• Faces a crystals flat side that meets at sharp
  edges and corners

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What kind of composition must a mineral have?

• A mineral must have a definite chemical
  composition it always contains certain elements
  in definite proportions most minerals are
  compounds

Cinnabar composed of the elements Mercury and
Sulfur
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What Is the Difference Between an Element and a
Compound?

• Element a substance composed of a single kind
  of atom. Ex. Hydrogen
• Compound Two or more elements combined so that
  the elements no longer have distinct properties
  Ex. Water H20

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How Do You Identify Minerals?

• Properties
• Density
• Crystal Shape
• Cleavage and Fracture
• Special Properties

• Hardness
• Color (this can vary)
• Streak
• Luster

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How Do You Determine a Minerals Hardness?

• Friedrich Mohs invented a test to describe and
  compare the hardness of minerals
• Mohs Hardness Scale
• Ranks ten minerals from softest to hardest

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How Does the Mohs Scale Work?

• Gypsum (2) will scratch talc (1), calcite (3)
  will scratch gypsum (2), fluorite (4) will
  scratch calcite (3), etc.

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What Is a Streak Test?

• The streak of a mineral is the color of its
  powder
• The streak color and the mineral color are often
  different
• To test rub a mineral against an unglazed tile
  (streak plate)

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What is the Luster of a mineral?

• Luster used to describe how a mineral reflects
  light from its surface
• Minerals containing metals are often shiny
• Earthy, waxy, and pearly

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What does Density have to do with Minerals?

• Each mineral has a characteristic Density
• Density or mass per unit volume Density
  mass/volume
• Displacement the volume of the displaced water
  equals the volume of the the sample

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What Kind of Shape does a Mineral have?

• Minerals have a crystal structure
• Cubic
• Hexagonal
• Tetragonal
• Orthorhombic
• Monoclinic
• Triclinic

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What is Mineral Cleavage?

• Cleavage A minerals ability to split easily
  along a flat surface
• The ability to break apart depends on the
  arrangement of the atoms in the mineral

Cubic Cleavage
Basal Cleavage
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What is Mineral Fracture?

• Fracture How a mineral looks when it breaks
  apart in an irregular way

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What Special Properties does a Mineral have?

• Fluorescence minerals that glow under
  ultraviolet light
• Magnetism - ex. Loadstone
• Chemical Reactivity- ex. Calcite gives off carbon
  dioxide
• Electrical Properties ex. quartz

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Section2 How are Minerals Formed?

• Two General Ways
• Crystallization of melted materials
• Minerals from Magma
• Crystallization of materials dissolved in water
• Minerals from Hot water solutions
• Minerals formed by evaporation

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What is Crystallization?

• Crystallization
• the process by which atoms are arranged to form
  a material with a crystal structure

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How do Minerals form from Magma?

• Minerals form as magma cools inside the crust, or
  as lava hardens on the surface

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What Effects Crystal Size?

• Rate at which magma cools
• Slower cooling forms larger crystals
• The amount of gas the magma contains
• The chemical composition of the magma

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How do Minerals Form from Hot Water Solutions?

• Magma beneath Earths surface has heated the
  water to a high temperature beneath Earths
  surface causing minerals to dissolve
• When this solution cools the elements and
  compounds leave the solution and crystallize as
  minerals

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What is a Solution?

• Solution A mixture in which one substance
  dissolves in another

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What do Pure Metals often form from Hot Water
Solutions?

• Veins A narrow channel or slab of a mineral
  that is much different from the surrounding rock

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How are Minerals Formed by Evaporation?

• As water turns to vapor it leaves behind the
  mineral
• Example A salt water solution leaves behind
  large crystals of salt

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Where are Minerals Found?

• Earths crust is made up of a variety of minerals
  however rare and less common minerals are
  usually located near plate boundaries because of
  volcanic activity and mountain building

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Section 3 How are Minerals Used?

• Minerals are the source of
• Metals ex. Aluminum, Iron
• Gemstones ex. Rubies and Sapphires
• Other Useful materials ex. Talc (talcum powder)

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Ore What?

• Ore - A rock that contains a metal or
  economically useful mineral
• Most metals, gemstones, and useful minerals must
  be separated from their ores

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What are the 3 Types of Mines?

• Strip Mines Giant equipment is used to scrape
  away soil
• Open Pit Mines Miners dig a tremendous pit
• Shaft Mines A network of tunnels that extend
  deep underground