SODIUM ALUMINOSILICATE 4A ZEOLITE MFG. Natural zeolites are analcite, chabazite, natrolite, stilbite, heulandite, and thomsonite. Synthetic production of zeolites implies either a gel process (sodium silicate and alumina) or a clay process (kaolin). Both methods are quite complex, requiring the exchange of various rare-earth oxides. The effectiveness of zeolite depends on its pore size, which may be as small as 4A.