Over 2000 minerals have been identified by earth scientists. Table 10d-2 describes some of the important minerals, their chemical composition, and classifies them in one of nine groups. The Elements Group includes over one hundred known minerals. Many of the minerals in this class are composed of only one element. Geologists sometimes subdivide this group into metal and nonmetal categories. Gold, silver, and copper are examples of metals. The elements sulfur and carbon produce the minerals sulfur, diamonds, and graphite which are nonmetallic.