GEOCHEMISTRY

Economic Minerals

Many materials used in today's modern industrial society are derived from one of Earth's natural mineral resources. A mineral resource is a natural concentration of a material that is economically feasible to mine. Mineral resources that contain metallic elements (copper, silver, iron, etc.) are found in the earth's crust and can combine with sulfur to form the mineral group known as sulfides. Pyrite (iron sulfide) and galena (lead sulfide) are examples of sulfide minerals. When a sulfide ore deposit weathers (exposed to air and water), it produces a new group of minerals known as the oxides (metals that combine with oxygen). In general, oxide minerals are recognized by their distinct colors (like azurite-blue, malachite-green, hematite-reddish, etc.), and sulfide minerals are recognized by their metallic appearance (luster).