An decorative element container module and a watch assembly incorporating the module are provided. The decorative element case module may include as walls lower and upper crystals, an outer ring for receiving an upper lip of the watch case body so as to secure the outer ring and for securing the upper crystal, and an inner ring including an upper portion for holding the upper crystal and a lower portion for securing the lower crystal. The outer and inner rings may have annular sloping walls to provide a unified reflecting surface for reflecting light to the decorative element container. The components of the module may be secured together and to the watch assembly without adhesive or glue, and may be disassemblable to facilitate removing and/or replacing decorative elements contained inside. The upper and lower crystals may have an anti-static coatings for discharging static electricity.