Great South Gems & Minerals

• Gneiss Granite •
(Georgia)

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• Gneiss Granite •
(Georgia)

Gneiss granite, metamorphic rock, feldspar, mica, schist, potassium feldspar, sodium feldspar, granite gneisses, diorite gneisses

Pronounced "nice", this is an excellent specimen of the process referred to as Gneiss. Many years ago at one of our local rock club meetings we had a professor from the University of Georgia speak to us about "Gneiss" rocks. He explained that as "birds of a feather flock together", the process Gneiss is one in of which like minerals go through a metamorphic process and come together in layers or bands. I thought that was a pretty good explanation.

Wikipedia states that Gneiss rocks are "common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks." This process takes place deep within the earth where time, heat, and pressure causes minerals of a type to come together.

Gneiss is coarser than schist and has distinct banding. This banding has alternating layers that are composed of different minerals. The minerals that compose gneiss are the same as granite. Feldspar is the most important mineral that makes up gneiss along with mica and quartz. Granite is commonly used by man as paving and building stone.

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