Post on 16-Dec-2015
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:• 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