MINERALOGY

• Mineralogy 


  is the branch of geology that involves aspects related to minerals such as formation, composition, occurrence, properties, and uses.
• International Mineralogical Association 


  recognizes approximately 5500 different kinds of minerals.
• HOW IS MINERAL DIFFERENT FROM ROCK?


  Minerals are homogeneous solids, rocks are combinations of minerals
• Silica


  A mineral commonly found in rocks and sand.
• Kaolinite


  A clay mineral used in ceramics and medicine.
• Gypsum


  A soft sulfate mineral used in construction.
• Naturally Occurring


  means it forms by itself in nature.
• Solid


  means that it is not a gas, liquid, or plasma
• With a Definite Chemical Composition


  means that the chemical composition can be expressed by a chemical formula.
• Highly Ordered Atomic Arrangement


  means that the atoms in a mineral are arranged in an ordered geometric pattern.
• Protons

  Positively charged particles in an atom.
• Neutrons

  Neutral particles found in an atom's nucleus.
• Electrons


  Negatively charged particles orbiting an atom's nucleus.
• In short, nearly every aspect of our lives—both biologically and socially —requires minerals.
• WHAT ARE MINERALS? 


  is a naturally occurring homogeneous solid with a definite (but not generally fixed) chemical composition and a highly ordered atomic arrangement, usually formedusually formed by an inorganic process.
• Crystal structure


  ordered arrangement of atoms
• All minerals are crystals.
• If the crystal structure is different, then we give the mineral a different name.
• amorphous


  A solid compound that meets the other criteria, but does not have a definite crystal structure
• FORMED BY AN INORGANIC PROCESS

  Not biological in origin and typically crystallizing from a liquid
• TWO TYPES OF BONDING


  ionic and Covalent bonding
• Minerals


  building blocks of rocks
• MINERAL IDENTIFICATION


  Physical

  Chemical

  Optical

  X-ray analysis
• COLOR 


  This is typically the first property and most basic way of identifying a mineral, however, it may also be the most difficult property to identify.
• STREAK


  -also called “powder color” of a mineral.

  -it refers to the colored residue left by the scratch of a mineral on an abrasive surface.

  -useful to distinguish two minerals that have the same color, but a different streak
• STREAK

  • e.g. Distinguishing Gold from Pyrite, Gold has yellow streak, Pyrite has a greenish black streak
• HARDNESS


  -it is the measure of the mineral’s resistance to scratching.
• HARDNESS


  -For example, if mineral A scratches mineral B, and mineral B does not scratch mineral A, then mineral A is harder than mineral B. If mineral A and B both scratch each other, then their hardness is equal.
• Frederick Mohs (1822).


  A scale to measure hardness was invented by German geologist and mineralogist

  
• CRYSTALLINE STRUCTURE 


  Particles are arranged in a repeating pattern. They have a regular and ordered arrangement resulting in a definite shape
• AMORPHOUS STRUCTURE 


  Comes from the Greek ámorphos, meaning “shapeless”. Particles are arranged randomly. They do not have an ordered arrangement resulting in irregular shapes.
• CLEAVAGE 


  is the tendency of a crystal to break along smooth, flat planes of structural weakness
• DIAPHANEITY


  -is a mineral’s degree of transparency or ability to allow light to pass through it. The degree of transparency may also depend on the thickness of the mineral
• TENACITY


  -describes the reaction of mineral to stress such as crushing, bending, breaking or tearing. Certain minerals react differently to each type of stress. Since tenacity is composed of several reactions to various stresses, it is possible for a mineral to have more than one type of tenacity
• TYPES OF TENACITY

  • Brittle
  • Sectile
  • Malleable
• Brittle 


  -mineral crumbles to grains or powder when hammered. -e.g., quartz, calcite, fluorite
• Sectile 


  can be separated with a knife, much like wax but usually not as soft.
• Malleable


  If a mineral can be flattened by pounding with a hammer, it is malleable. All true metals are malleable. -e.g., silver, gold
• Ductile

  • A mineral that can be stretched into a wire is ductile. All true minerals are ductile. -e.g., gold
• Flexible but inelastic

  • Any mineral that can be bent, but remains in the new position after it is bent. -e.g., copper