The theoretical formula for kaolinite is Si2Al2O5(OH)4 (other formulas are Al2O3·2SiO2·2H2O and Al2O7Si2. 2H2O), which has a molecular weight of 258,071 g/mol. Kaolinite is build up from pseudohexagonal triclinic crystals with diameter 0,2–10 μm, with thickness 0,7 nm and its density is 2,6 g/cm3 [5, 7 – 9].