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Does the position of the rock material in the earth affect the type of mineral that forms, for example, the density of the material and therefore forming different minerals? Are there any examples that you could give me, or certain test results?
Answer 1:

Yes - different minerals form at different temperatures and pressures. The process by which this happens in the Earth is called metamorphism, and rocks whose minerals have been altered by heat and pressure in this way are called metamorphic rocks. For example, shale is made out of quartz and clay minerals (e.g. kaolinite). If you metamorphose it, it turns into slate, then phyllite, and finally schist, and what is happening to cause this transition is that the clay minerals are turning into micas (mainly muscovite). If you continue to metamorphose it will become agneiss, in which the muscovite mica will become chlorite and then biotite. Eventually, you melt the rock, and when you crystallize that out, what had been clay is now a mix of biotite, hornblende, and variousfeldspars.


Answer 2:

Rocks are made up of minerals. In general, the deeper one goes in earth the higher the density of the rock and hence the minerals making up the rock tend to be denser.

So graphite is the stable form of element Carbon at the surface but at depths > about 150 km, diamond is the stable form of carbon.



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