Within the scope of investigations for assessing the weathering behavior of building stones it has been shown that one can quantify the results obtained by the classical sodium sulphate crystallization test, using a new method, in a better way than before. It has been demonstrated that the Weibull distribution may be used to describe the course of the mass change of the specimens disintegrating uniformly. So it has become possible to characterize the curve being specific for each material and depending upon the respective procedure by means of two parameters. The new evaluation method, however, reaches its limits when the specimen cubes are not liable to transition into residual bodies being similar to spheres. The results obtained by this function make possible a correlation between the behavior in the crystallization test and other characteristic data of a material.