To be classified as a mineral, a substance must have the following four characteristics: it must be organic, naturally-occurring, solid and a have a definite chemical composition. A substance must also have an ordered internal structure.
To be naturally-occurring, the substance must not be man-made. The inorganic requirement states that the substance must not be constructed by an organism. The solid characteristic eliminates any substance that is a liquid or gas. Definite chemical composition means that the substance must have a chemical composition that falls within a specific range. The characteristic that requires the substance to have an ordered internal structure states that the atoms are arranged in a repeating pattern.