Igneous Rocks

1
Igneous Rocks From Fire

• Igneous rock forms when lava or magma cools and
  hardens to form crystals (crystallization)

2
Two Major Groups of Igneous Rocks Classified
according to where the rock crystallizes

• Intrusive Igneous Rocks when the cooling of
  magma occurs deep below the crust.
• Extrusive Igneous Rocks when the rapid cooling
  of lava or melted rock occurs on the earths
  surface.

3
Texture the size of the crystals in the rock.

• Coarse grained crystals can be seen with the
  naked eye
• Fine grained no visible crystals or the
  crystals are too small to be seen with the naked
  eye

4
Composition the materials that form in igneous
rocks depends on the chemical composition of the
magma or lava from which the rock cools and
crystallizes.

• Felsic Igneous Rocks
• fel feldspar sic containing oxygen and
  silicon
• Light in color
• High in Silica
• Main minerals are feldspar and quartz
• Low Density
• Mafic Igneous Rocks
• Ma magnesium fic ferric iron
• Dark in color
• Low silica
• High density