Naturally occurring solids with ordered atomic structures and defined chemistries are called minerals. Each mineral species has a characteristic composition or compositional range and a specific crystal structure. Quartz, calcite, and feldspar are among the most abundant.

Minerals form from cooling melts, precipitating solutions, or solid-state reactions during metamorphism. Physical properties such as hardness, cleavage, luster, and density reflect the underlying structure and bonding. These properties allow identification in hand sample and are the basis of many industrial uses.

More than 5,000 mineral species are known, yet a few dozen rock-forming minerals make up the bulk of the crust. Ore minerals concentrate valuable elements; industrial minerals supply raw materials for construction and manufacturing. Mineralogy underpins the study of rocks and the economic extraction of resources.

• Naturally occurring inorganic solid
• Definite chemical composition and ordered structure
• Identified by physical and chemical properties
• Building blocks of rocks