How far down does granite go into the earth?

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ladyvols1 eNotes educator| Certified Educator

We see granite everywhere.  We see it as counter tops in many kitchens and we see it as flooring in many homes.  Granite can be used indoors or outdoors because it is so resistant to cracking, scratching, staining, or burning.  Granite is an intrusive rock that begins as a molten mass. Most scientists and Geologists agree that it forms 25 to 40 Kilometers below the earth’s surface.  It is an igneous rock and is formed over time from the molten magma.  The minerals of quartz, mica, and feldspar make up the stone we know as granite.  Granite is mined all over the world, and its colors and characteristics are dependent on where it is located.

"Granite, which makes up 70–80% of Earth's crust, is an igneous rock formed of interlocking crystals of quartz, feldspar, mica, and other minerals in lesser quantities. Large masses of granite are a major ingredient of mountain ranges. Granite is a plutonic rock, meaning that it forms deep underground. Slow cooling gives atoms time to migrate to the surfaces of growing crystals, resulting in a coarse or mottled crystalline structure easily visible to the naked eye."


giorgiana1976 | Student

 It can be said that Granite is the most common rock in the Earth's crust, being present in tectonic or sedimentary areas .

Granite is an igneous rock solid, with coarse grain (with crystal size of several millimeters), formed at large depths, containing mainly quartz, feldspar and dark minerals as mica.

Characteristic for granite, also called platoon, are great depths where it is formed, the rocks that are formed at shallower depths then 2 km, are known as volcanic or "gangue rocks", (sterile) in mining.

As the magma cooling process occurs at relatively large depths, magma cooling occurs slowly, minerals' crystallizing  happening according to their melting point, so dark minerals with high melting point, which typically have a bigger density,  solidify at the top, followed by feldspar and quartz.

In the room or nest of granite,it will be found minerals with smaller density,  like feldspar, and, closer to the surface, quartz .

By tectonic movements,  subsequent to granite formation, or by processes of erosion and transport of water, wind, granite covering layers are removed, this one appearing on the surface and being put to turn weather and sunlight, which leads to a change in its color in a yellowish hue, softer minerals being eroded.The appearance of granite, is different in it's mass  can be seen the  crystals of  minerals of several millimeters size, granite  color varying from open gray to blue, red, yellow.