California Code
ARTICLE 2 - Definitions
Section 14537.

14537. (a) “Gypsum” means calcium sulfate dihydrate, a mineral used in the fertilizer industry as a source of calcium and sulfur which is also known as landplaster.

(b) “Phosphatic sulfate gypsum” means a by-product of calcium dihydrate from the manufacture of phosphoric acid, also known as phosphogypsum.

(Added by Stats. 1990, Ch. 504, Sec. 2.)