How thick is a single pane glass window typically? I recently broke the window in my dorm. I was resting my foot on the window, and it just broke underneath. I measured the thickness of the broken window, and found it only to be an eighth inch. I feel almost like I should be the one complaining... Source(s): average window thickness: https://bestanswer.im/e14/average-window-thickness.
By Andrew Alden. Metamorphic rocks are the third great class of rocks. These are what happens when sedimentary and igneous rocks become changed, or metamorphosed (changed in form), by conditions underground. The four main agents that metamorphose rocks are heat, pressure, fluids and strain.
A metamorphic rock used to be some other type of rock, but it was changed inside the Earth to become a new type of rock. The word metamorphism comes from ancient Greek words for change (meta) and form (morph). The type of rock that a metamorphic rock used to be, prior to metamorphism, is called the protolith. During metamorphism the mineral content and texture of the protolith are changed due to changes in the physical and chemical environment of the rock. Metamorphism can be caused by burial, tectonic stress, heating by magma, or alteration by fluids. At advanced stages of metamorphism, it is common for a metamorphic rock to develop such a different set of minerals and such a thoroughly changed texture that it is difficult to recognize what the protolith was.