Alforsite is a mineral, Ba5Cl(PO4)3, composed of barium, phosphorus, chlorine, and oxygen. It was discovered in 1981, and named to honor geologist John T. Alfors of the California Division of Mines and Geology for his work in the area where it was discovered.

Alforsite is a hexagonal colorless crystal in the chemical class phosphates and the group apatite. It is found in certain parts of central California, primarily Fresno, Mariposa, and Tulare Counties. It has also been found in Baja California, Mexico.