Typically schists contain significantly lower levels of quartz than gneisses and many other rocks, but quartz-sericite schist is a variety of the rock than contains a greater amount of the mineral than normal. As its name implies, this type of schist also contains significant amounts of sericite, which is a fine-grained type of either muscovite or paragonite, both of which are relatively abundant silicate minerals. Found in various locations, one of the best known examples of quartz-sericite schist occurs in Canada, where it is a source of economically important gold deposits