Ace the 2026 Earth and Life Science Challenge – Unlock the Secrets of Our Planet!

The main idea here is what defines a mineral. A mineral is a natural, inorganic solid with a definite chemical composition and an orderly crystalline arrangement of atoms. That crystal lattice and fixed composition are what make minerals the fundamental building blocks of rocks—rocks are formed from minerals glued together, rather than from rocks themselves.

Crystals describe the orderly pattern inside a solid, but not all crystals are naturally occurring or inorganic, and they don’t by themselves specify what rocks are made of. Elements are pure substances, which some minerals can be, but rocks are typically composed of minerals (which are compounds or elements arranged in crystals), not pure elements. Rocks are the larger aggregates, so they’re described by what they’re built from—minerals.