Nucleation and crystal growth of Cd5H2(PO4)(4) . 4H(2)O has been studied by mass crystallization experiments at different initial supersaturations by recording pH of solutions as a function of time and determining crystal size distribution at the end of experiments. Surface free energy was determined from critical supersaturation; a value of 62 mJ/m(2) was found. The crystal growth mechanism is spiral growth at low supersaturation and surface nucleation or a mixture of both at high supersaturation. Different stages could be distinguished in the latter range, corresponding to different crystal faces as rate determining. For the corresponding edge free energies lambda(hkl), the following values in pJ/m were found: 62, 27 and 11.8 for (100), (110) and (001), respectively. For these three faces, three different values of rate constants for spiral growth were found as well. (C) 2002 Elsevier Science B.V. All rights reserved.