A crystal is a solid material whose atoms or molecules are arranged in a highly ordered, repeating pattern, which gives rise to its characteristic geometric shape. A crystal can be made up of a single type of molecule, such as a diamond, or a complex arrangement of different types of molecules, such as in quartz. On the other hand, a mineral is a naturally occurring, inorganic substance that has a definite chemical composition and crystalline structure. In other words, all crystals are solid materials with a highly ordered structure, but not all crystals are minerals.
