Natural or synthetic zeolites are microporous crystalline aluminosilicates, consisting of a three-dimensional structure of [SiO4]4- and [AlO4]5-. Zeolites have unique ion exchange and sorption properties. They are widely used in wastewater treatment, construction, act as a catalyst, gas separation and ion exchange in industry. Water TreatmentZeolites are used in a large number of water treatments such as water softening and purification from ammonia, heavy and radioactive metals. In addition to this, zeolites are used as sorbents for the removal of organics, microorganisms and anions, for seawater desalination membranes and fill materials for reactive permeable barriers. Wastewater contains traces of heavy metals such as Zn, Cr, Pb, Cd, Cu. These heavy metals must be removed because they cause serious environmental problems. Heavy metals are removed along with other technologies including chemical precipitation, ion exchange, adsorption, membrane filtration, coagulation flocculation, flotation and electrochemical methods. Natural zeolites have shown good ion exchange capabilities for cations, such as ammonium and heavy metal ions. To have a high adsorption capacity of organic matter and anions, the modification of natural zeolites can be performed by different methods, such as acid treatment, ion exchange and surfactant functionalization. In addition to the removal of heavy metals, natural zeolites are used to remove ammonia and humic acid from surface waters. The removal of contaminants depends on the pH value, the initial concentration of humic acid and ammonia, the temperature and the contact time. Zeolite shows the best ammonia and humic acid removal performance at a pH close to that of natural water. Additionally, natural and modified zeolites are used to...... half of the paper...... to produce building materials. Over 60% of the world's zeolite production is consumed by the construction industry in China to produce lightweight, high-performance concrete. Zeolite can be expanded by heating to approximately 1200ºC to produce lightweight aggregates with a density of approximately 0.8 kg/cm3. With such properties, zeolite can be used to make lightweight building blocks or, for example, decorative wall panels. The porous structure of natural zeolite allows it to retain water which can increase curing time and increase strength during curing. Zeolites also have much higher cation exchange capacities than other natural pozzolans where it prevents the alkali-silica reaction. Natural zeolite can also be used to make ceramics, glazes and frits. However, the full potential of zeolites in the ceramic industry has yet to be realized