Though primarily composed of quartz and feldspars, granite also frequently contains small amounts of hornblende, micas, and other minerals. Moreover, the proportion of plagioclase to alkali feldspar may differ in granite samples, which is often utilized as the starting point for granite classifications. Alkalic, or alkali, granites, for instance, are those in which the alkali feldspar content significantly exceeds the plagioclase. These types of rocks characteristically contain pyroxenes and sodic-amphiboles. In the United States, samples of alkalic granite can be found in New England, but they also occur notably in Norway and Nigeria.