The microstructure of the dispersed phase in an aqueous dispersion of an organic colloid undergoing transformation from a sol to a macroscopic gel is studied by wide-angle X-ray diffraction. On comparing the X-ray diffraction data with previously published electron micrographs (Chari et al., 1993), we find that the initial particles are amorphous (the diffraction pattern at this point is characterized by broad peaks of relatively low intensity), whereas the fibrillar elements that appear at a later stage are definitely crystalline. The "gel" consists of a network of these crystalline fibrils.