Chapter 3 Section 1

 A mineral is ◦ Naturally occurring ◦ Inorganic- it has no carbon in its chemical formula ◦ Has a definite chemical composition ◦ Has an orderly arrangement of atoms ◦ 4000 different minerals

 Crystalline- means that the atoms are arranged in a pattern that keeps repeating over and over

 Solid in which the atoms are arranged in orderly, repeating patterns.  Six major shapes to crystals ◦ Cubic ◦ Hexagonal ◦ Tetragonal ◦ Orthorhombic ◦ Monoclinic ◦ Triclinic

 1. From Magma  2. From Solution

 After magma is released from below Earth’s surface it begins to cool  As it cools, atoms lose heat and move together forming compounds.  These compounds arrange themselves in regular repeating patterns or crystals  If magma cools quickly, the crystals are large  If magma cools slowly, the crystals are small

 Crystals also form from minerals dissolved in water  Water can evaporate leaving crystals behind like halite or salt crystals  If too much substance is dissolved in a water then it can precipitate out forming a crystal

 Most of Earth’s surface is made up of 8 minerals  Oxygen- 46.6%  Silicon-27.7%  Aluminum- 8.1 %  Iron- 5.0 %  Calcium-3.6%  Sodium- 2.8 %  Potassium- 2.6%  Magnesium 2.1%  Other 1.5%

 Most of the common rock forming minerals contain silicon and oxygen  They are called the silicates  They contain silicon, oxygen, and 1 or 2 more elements