The growth simulations of synthetic quartz crystals grown on seeds with industrialized sizes and orientations were shown on the procedure by means of the setting of virtual lengths between the seed center and principal crystal faces to be grown. The virtual lengths needed for simulations are calculated on the given sizes and shapes of seeds, X-bar, Y-bar and rectangular Z-plate. The simulations of growth processes are executed as a function of growth time under the model values of growth rates on principal crystal faces, in, R, r, Z, and the so-called S. By the comparison of geometrical sizes of as-grown crystal faces with simulated faces, the growth rates of principal faces are quantitatively evaluated in the commercially produced quartz crystals grown from the rectangular Z-plate seeds. The growth rates of R- and r-faces at the upper and lower sides of grown crystals show somewhat different values which may be due to the direction of convection flow in autoclave. (C) 2002 Elsevier Science B.V. All rights reserved.