The crystal growth of calcite at a low temperature range was carried out by the hydrothermal method usingamorphous calcium carbonate which has excellent solubility in water. Amorphous calcium carbonate was prepared by thewet chemical reaction of a stoichiometric mixture of CaCl2 and Na2CO3. An important factor was the reaction temperaturemethod, NH4NO3 solutions were found to be the most promising solvents to grow calcite single crystals. The hydrothermalconditions for high growth rates of calcite single crystals were as folows: starting material: amorphous calcium carbonate,solvent: 0.01 m NH4NO3, temperature: 180oC, duration: 30 days. And properties of calcite single crystals were folows:dislocation density: 106~107 cm2, UV-visible transmittance: about 80 % from 190 to 400 nm and birefringence: 0.17~0.18.Also, it can be known from the FT-IR results that the absorption peak by injection of HCO3 and OH ions was not shown.Key words Amorphous calcium carbonate, Hydrothermal method, Calcite single crystal, Polarization device