What is a Rock?

• What is a Rock?


  Rock or stone is a natural substance, a solid aggregate of one or more minerals
• Mineral


  A naturally occurring inorganic substance that has a specific chemical composition and characterisitic crystalline structure
• Polymorphs


  Both Minerals have the same chemical composition but they have a different arrangement of the atoms
• Native Elements


  A mineral composed of atoms of only one type
• Crystals

  Minerals often form liquids

  If the liquid is cooled slowly the energy is reduced, atom movements slow and they organise themselves into patterns

  Produces Crystals
• Glass


  If it’s cooled quickly, it doesn’t have time to organise so random arrangement stays - Glass
• Slower Cooling = Larger Crystals


  Minerals grow from the centre outwards, faces can vary in size by the angles between them are the same for each mineral
• Elemental Composition


  99% of the Earths crust by weight is made of just 8 elements
• Orange = Oxygen

  Snakes = Silicon

  Are = Aluminium

  In = Iron

  Cupcakes = Calcium

  Special = Sodium

  Potato = Potassium

  Mochi = Magnesium
• Compounds


  Composed of two or more different types of atoms which are chemically bonded together
• Six major compounds


  Oxides, Halides, Sulphides, Sulphates, Carbonates, Silicates
• Oxides


  Minerals composing atoms of oxygen plus other metal atoms
• Sulphides


  Minerals comprising atoms of sulphur plus other metal atoms
• Halides


  Minerals comprising Halogens plus other metal atoms
• Carbonates


  Minerals comprising carbon and oxygen atoms plus other metal atoms
• Sulphates


  Minerals comprising sulphur and oxygen atoms plus other metal atoms
• Silicates


  Minerals comprising silicon and oxygen atoms plus other metal atoms
• Silicates are the most common rock forming minerals and account for just other 93% of the earths crust by mass