Minerals are not the building blocks of crystals. Minerals are naturally occurring inorganic solids with a definite chemical composition and crystalline structure. Crystals, on the other hand, are solid materials with a regular and repeating arrangement of atoms, ions, or molecules. While many minerals can form crystals, not all crystals are made of minerals. For example, some crystals are made of organic compounds, such as sugar, while others are made of inorganic compounds, such as salt.