Minerals

• Minerals are inorganic compounds that are solid at room temperature and are not living organisms.
• A mineral is any object that exhibits the following characteristics:

  • Naturally occurring - minerals from natural geologic processes
  • Generally inorganic - organic compounds are not considered minerals
  • Solid substance - only solid crystalline substances are considered minerals
  • Orderly crystalline structure - minerals are made up of atoms are arranged in an orderly manner
  • Definite chemical composition that allows for some variation
• Rock

  any solid mass of mineral or mineral-like matter that occurs naturally. Aggregates of several different minerals
• Diagnostic Properties

  • Taste
  • feel
  • shape
  • streak
• Ambiguous properties

  • color
• Luster


  appearance or quality of light reflected from the surface of a mineral
• MInerals that are shiny like metal, regardless of color are said to have metallic luster
• Color 


  the wavelength of light reflected from a mineral's surface is a diagnostic property
• Streak


  the color of the mineral in powdered form
• Fool's Gold


  Pyrite
• Transparency


  ability to transmit light
• Opaque


  no light transmitted
• Translucent


  light, but not an image is transmitted
• Transparent


  light and image are both transmitted
• Crystal shape/habit


  characteristic shape of crystals
• Hardness


  resistance of a mineral to abrasion by rubbing
• Mohs hardness scale

  
• Earth's crust and oceans are home to a wide variety of useful and essential minerals
• Common uses of basic metals

  • Aluminum in beverage cans
  • Copper in electrical wiring
  • Gold and silver in jewelry
• Pencil-lead contains the mineral graphite
• Bath powders and many cosmetics contain the mineral talc
• Dentists use drill bits impregnated with diamonds to drill through tooth enamel
• Practically every manufactured product contains materials obtained from minerals
• Every geologic process in some way depends on the properties of basic earth materials
• Mineralogy


  The study of minerals
• Mineral


  Any naturally occurring inorganic solid that possesses an orderly crystalline structure and a definite chemical composition that allows for some variation
• Characteristics of a mineral

  • Naturally occurring
  • Inorganic crystalline solid
  • Definite chemical composition with some variation
• Synthetic materials produced in a laboratory or by human intervention are not considered minerals
• Organic compounds made by living things are generally not considered minerals
• Inorganic compounds secreted by marine animals, such as calcium carbonate or calcite in shells and coral reefs, are considered minerals if they become part of the rock record
• Orderly crystalline structure


  Atoms or ions arranged in an orderly repetitive manner
• Naturally-occurring solids like volcanic glass or obsidian that lack repetitive atomic structures are not considered minerals
• Definite chemical composition with some variation

  Most minerals are chemical compounds with compositions that can be expressed by a chemical formula, but some can vary within specific well-defined limits
• Ice can be considered a mineral based on the definition
• Rock


  Any solid mass of mineral or mineral-like matter that occurs naturally as part of our planet, usually an aggregate of several different minerals
• Some rocks are composed of non-mineral matter like volcanic glass, pumice, and coal
• Minerals have definite crystalline structures and chemical compositions that give them a unique set of physical and chemical properties shared by all specimens of that particular mineral
• Diagnostic properties


  Mineral properties that are useful in identifying an unknown mineral, like a salty taste for halite
• Ambiguous properties


  Mineral properties that vary among different specimens of the same mineral, like color
• Luster


  The appearance or quality of light reflected from the surface of a mineral