In geology a mineral is:

  • a naturally occurring solid
  • formed by geologic processes
  • has a crystalline structure
  • has a definable chemical composition
  • almost all minerals are inorganic


Naturally occurring:

  • formed in nature, not in factories
  • but... chemists have learned how to manufacture synthetic minerals with almost identical characteristics


Formed by geologic processes:

  • mostly but not always
  • solid, crystalline materials produced by organisms are considered biogenic minerals



  • a state of matter


Crystalline structure:

  • atoms are in a fixed, orderly pattern


Definable chemical composition:

  • it is possible to write a chemical formula
  • some minerals contain only one element but most are compounds of two or more elements
  • diamonds and graphite are made entirely of carbon
  • Quartz has the formula: SiO2



  • organic chemicals consist of molecules that contain carbon
  • form either in living organisms or have structures similar to those formed in living organisms
  • Examples of organic molecules:
    • sugar
    • fat
    • plastic
    • propane
    • protein
  • Almost all minerals are inorganic


Glass is not a mineral:

  • both are solid
  • minerals are crystalline
  • glass is not crystalline.
    • the atoms, ions or molecules are not ordered but are arranged in a semi-chaotic way



Mineral Classes

  • silicates
  • sulfides
  • oxides
  • halides
  • carbonates
  • native metals
  • sulfates