Minerals are solid, naturally occurring chemical substances with structures that are highly organized atomically. They also have very specific physical properties, and are formed through biogeochemical processes. Though they may look like rocks to the untrained eye, minerals differ from rocks substantially in that they have only one specific chemical composition, while rocks are a mix of many kinds of minerals or mineraloids.
Some of the many chemical compositions minerals can have, ordered approximately by their abundance in the Earth’s crust from highest to lowest, include the Silicate class, the Carbonate class, the Sulfate class, the Halide class, the Oxide class, the Sulfide class, the Phosphate class, the Element class, and the Organic class. Minerals are a critical commodity to many industries following their mining and processing and form a material input to chemicals manufacturing, metallurgy, building materials manufacturing, electrical grid infrastructure, electronics, glass products, vehicles, and high-technology. Rare earth minerals or rare earth elements are particularly crucial to numerous energy efficiency and renewable energy technologies.
Common oxide minerals include chromite, hematite, and magnetite. Economically, minerals from the Sulfide class are arguably just as valuable as metal ores, and include chalcopyrite, or copper iron sulfide, galena, or lead sulfide, and pentlandite, or nickel iron sulfide. The Element class is home to those minerals called native metals or intermetallic elements, such as gold, silver, and copper, as well as natural alloys. The Element class is also where one could find semi-metals and non-metals, such as bismuth, graphite, and sulfur.