Minerals
Section 2.2
Section 2.2
A mineral is a naturally occurring, inorganic solid with an
orderly crystalline structure and a definite chemical
composition.
• In order for a material to be considered a mineral it must
have the following characteristics:
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•
•
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Naturally Occurring – not man made
Solid Substance – solid in normal temp.
Orderly crystalline structure – atoms arranged in an order
Definite chemical composition – has a specific chemical
formula
• Generally considered inorganic – not living
Section 2.2
• Which of the following items are minerals and which
are not?
Salt
Coal
Silver
Steel
Sugar
Gold
Glass
Wood
Concrete
Snowflake
Seashell
Bone
Section 2.2
• How minerals form:
• Crystallization from magma – as magma cools, elements
combine to form minerals ( Quartz, Feldspar, Muscovite)
• Precipitation – as Earth’s water evaporate dissolved
substances can react to form minerals (Halite & Calcite)
• Pressure & Temperature – when minerals are exposed to
pressure or temp their atomic structure can change to
form new minerals (Talc & Muscovite)
• Hydrothermal solutions – extremely hot solutions come
into contact with minerals and cause chemical reactions
that form new minerals (Bornite & Chalcopyrite)
Crystallization of
Magma
Mineral Groups
• Minerals are classified into groups based on their
chemical composition
• Silicates
• Most common group of minerals
• Contain Silicon (Si) and Oxygen (O)
• The structure is a tetrahedron, which consists of one silicon
atom and four oxygen atoms
Mineral Groups
• Carbonates
• Second most common mineral
• Contain Carbon (C), Oxygen (O) and one or more other
metallic elements
• Calcite (CaCO3) is the most common carbonate
• Limestone & Marble contain carbonates
• Oxides
• Contain Oxygen (O) and one or more other elements,
usually metals
• Corundum (Al2O3) and Hematite (Fe2O3) are examples
Mineral Groups
• Sulfates & Sulfides
• Contain Sulfur (S)
• Can form from mineral rich waters or thermal solutions
• Pyrite (FeS2) & Galena (PbS) are examples
Mineral Groups
• Halides
• Contain a halogen ion plus one or more other elements
• Includes the elements Fluorine (F) & Chlorine (Cl)
• Halite (NaCl) is an example
• Native Elements
• Are elements in their pure form
• Gold (Au), Silver (Ag) and Copper (Cu) are examples
• Some form from hydrothermal solutions
Mineral Groups
• Copper