A mineral is a naturally occurring, solid substance with a specific chemical composition and a crystal structure, such as quartz, mica, or feldspar. Rocks are typically made up of combinations of different minerals mixed together.
Some minerals are valuable because of their beauty, like gemstones such as diamonds and emeralds, while others are essential to industry and technology, such as copper for wiring or silicon for computer chips. Geologists identify minerals by testing properties like hardness, color, luster, and how they break.
Minerals and rocks are also the source of many natural resources people depend on daily, including metals, fuels, and building materials. Because these resources take enormously long periods to form naturally, mining them responsibly and recycling materials like metal are important for using Earth's resources sustainably.