Granite is formed deep below the surface
of the earth, possibly at a depth of 30 miles. The igneous
rock is the result of mounting forces and of plate
tectonics. The pressure and friction of one plate running over
another plate creates a meltdown zone. Molten rock at this
depth will be pushed upward toward the earth's surface.
This creates some volcanoes and some granite
magma chambers. The volcanoes lava will not make granite because
it will cool too quickly. It is in the magma chambers that a slow
cool down of melted rock will allow for the development of larger
crystals. It is in the magma chambers that the forces of
extreme heat, steam, great pressure, and vast amounts of time
produce granite.
The magma chamber may take millions of years
to cool, creating fantastic crystals, beautiful colors, and visual
movement. Granite is composed of quartz, potassium feldspar and
sodium feldspar, as well as the mirror constituents of Muscovite,
Biotite and Amphibole (the last two being dark silicates). As
more millions of years pass the magma chamber inches its way
upward where it may finally be exposed as an outcropping or a
mountain.
Examples of exposed granite would be Pike's
Peek, Mount Rushmore or Yosemite National Park. Most magma chambers
never make it to the surface. As granite is nearly as hard as
diamond, it takes a diamond to cut it.
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