What is the difference between a mineral and a rock?
A mineral is a chemical compound with a specific chemical formula and a very precise internal structure. Rocks are the natural “hard parts” of the earth, and are composed of one or more minerals or mineral grains. Quartz, feldspar, mica, and hornblende taken individually are minerals. Grains of quartz, feldspar, mica, and hornblende mixed together form granite, which is a rock. Although most rocks are formed from several different minerals, some rocks exist that are composed of a single mineral. An example of this is the rock quartzite, which is composed entirely of the mineral quartz.
