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