Large Crystals Of Granite Surrounded By Mica Schist

It has mica grains large enough to see with the naked eye which means it glitters and sparkles.

Large crystals of granite surrounded by mica schist.

Hi kevin my understanding is schist is a coarse grained metamorphic rock that consists of layers of different minerals mica among them along with chlorite talc hornblende and graphite and can be split into thin irregular plates. Schist and slate are very similar in that they are made from the same rock types except it is subjected to more heat and pressure. Large crystals cause schist rocks to reflect lots of light which gives it a very shiny appearance. The large black grain is the garnet the red elongate grains are mica flakes.

Where as mica is it s own mineral and forms in flaky layers. Mica is made up of thin sheet like layers of atoms that reflect light like a mirror. The most common porphyroblasts in metapelites metamorphosed mudstones and siltstones are garnets and staurolites which stand out in well foliated metapelites such as schists. Schist is a metamorphic rock made mostly of mica mineral formed under the heat and compression of tectonic forces.

The mountains are primarily composed of granite surrounded by an envelope of mica schist and much older rocks such as quartzite. This is a microscopic view of a garnet grain that has grown in schist. It is often referred to as schistosity because of its large mica flakes. Garnet mica schist in thin section.

The black gray and white grains are mostly silt or smaller size grains of quartz and feldspar.