+Crystals are [solids](/wiki/solid) where atoms, molecules, or ions are arranged in a precise, repeating internal structure. This fundamental order often results in distinct, geometric forms, shaping everything from common salt to precious [minerals](/wiki/mineral) found deep within the Earth.
+## See also
+- [Gemstone](/wiki/gemstone)
+- [Crystal structure](/wiki/crystal_structure)
+- [Physics](/wiki/physics)