Concept:Minerals are naturally occurring crystalline substances. Some minerals are ores from which metals are extracted.Explanation:Bauxite is the ore of aluminium.Hematite and limonite are ores of iron.Gypsum is formed when plaster of Paris (CaSO₄·½H₂O) reacts with water to give CaSO₄·2H₂O.Gypsum is not a naturally occurring mineral; it is a product of a chemical reaction.Therefore, among the given options, gypsum is not a mineral.Answer:Gypsum (Option B)