Victorian 18K agate Cameo of the Goddess Demeter decorated brooch

One highly decorated Victorian Mourning brooch pin, crafted in solid 18K yellow gold. A thin rope twist link embellished on the side of the Cameo. The cameo is carved from agate stone, it measures 30. x 21.88mm. Four side has scroll etching. There is compartment can be open at the back. The piece can be worn as pendant or brooch. 
It measures 45.0 x 40.0mm, weight 17.9gm, no hallmark, tested for 18K