Earth is the most versatile of all the planets in the solar system. Above the layer of soil, the crust of the earth, there are mountains touching the skies and below the crust there are such hidden wonders that man can’t even think of. Gneiss rocks are another example of this kind of wonder!
Gneiss rocks are distinctive in their characteristic of being able to exist in two forms: metamorphic rocks and igneous rocks. (Encyclopedia)
Gneiss rocks have clear layers of sediments that make up the texture of the rock with some important minerals and varied concentrations of elements like mica, hornblende, and garnet. (Encyclopedia)
Gneiss rock is abundant in quartz and feldspar and the banding in the rocks is mainly due to varying concentrations of these minerals in the rocks. (Britanica)
Gneiss rocks are formed due to regional metamorphism in which the layers of the rocks are set by the mineral deposition; and ultimately, due to high temperature and pressure, the layers transform into solid rocks. Â (Geology Blog)
Most of the earth’s lower crust is all made up of gneiss rocks. (Geology Blog)
Having known that gneiss rocks are formed out of layers, one might think that they break up into layers too. But actually, these rocks seldom crack at the edges of the layers. They always break in an irregular manner. (Hyperphysics)
The name “Gneiss” has been extracted from a German word that means “to spark”. This is probably due to the fact that the rock glitters with tiny mica particles embedded in the layers.
Canada is the place having the honor to host the oldest rock ever found: a gneiss metamorphic rock which is 3.6 billion years old! (Think Quest)
The layers of the gneiss metamorphic rocks start appearing in the earth’s crust at a depth of 12 km to 15 km. (Think Quest)