Single crystals of gallium orthophosphate (GaPO4) being isostructural to low-quartz are usually grown from strong acidic solutions. To maintain a good structural perfection of the crystals, the growth rate of the respective growing interface has to be controlled. It is shown that striations are formed due to growth temperature changes, which are marked by a higher density of mother liquid inclusions. These induced striations have been used to determine the individual growth rates of the pinacoid {011} and the rhombohedral faces {011} at GaPO4 single crystals. (C) 2002 Elsevier Science B.V. All rights reserved.