Hydroxide mineralizers are also used to control the alumina/silica ratio of zeolites. A typical recipe for the production of a zeolite includes the mineralizer, the solvent, the seed crystal, a nutrient consisting of silica (SiO) and alumina (AlO), and a template. Templates are cations that direct the polymerization of the anionic building blocks to form a certain zeolite structure. Different templating cations lead to different zeolite structures. Typical templates include tetramethylammonium (TMA), sodium (Na) and potassium (K). Different zeolites can also be formed by changing the ratios of the nutrient source, the type of mineralizer or the temperature and pH of the reaction. At high pH, zeolites with high alumina content are formed, because hydroxides prevent the ability of silica to condense and oligomerize through the reaction shown above.  At lower pH, zeolites with high silica content are favored.