X-ray diffuse scattering from boracite in the cubic phase shows the existence of fluctuation domains, having the form of cigarillos oriented with their main axis parallel to 〈100〉 directions. The relative magnitude of the at. displacements of the metal and halogen atoms in the soft fluctuation corresponds to the conservation of the center of mass, which seems to indicate that the simplest soft optic mode condensation picture of the displacive phase-transition theory may apply to boracites.