GaN crystal could be grown by ammonothermal method using NH4Cl mineralizer. Inner wall of autoclave is covered with Pt so as to prevent possible contamination from autoclave. Reaction was carried out with supercritical ammonia at temperatures of 500degreesC and pressures of 135 MPa. Recrystallization of GaN was also confirmed under the condition of 500degreesC and 120 MPa, which is the lowest reaction pressure ever reported for GaN growth by ammonothermal method. These results show the possibility for the real industrial volume production of GaN by ammonothermal method. (C) 2003 Elsevier B.V. All rights reserved.