However, if the shale was in an area that was exposed to higher pressures and moderate temperatures, it might have been transformed into schist. The clay in the shale could have been converted to mica, which gives schist its shiny look.

Granite is a light-colored rock made of quartz, feldspars, mica, and small amounts of hornblende. The crystals of all these minerals are randomly arranged. Granite can be metamorphosed into a rock called gneiss (pronounced like "nice"). Gneiss has about the same mineral composition as granite, but the pressure of metamorphism causes the minerals to line up, giving gneiss a distinct banded appearance. Schist may also be converted into gneiss, if increased pressure and temperature is added. Metamorphic rocks are a mixed up group that have been under a lot of stress!