Our latest obsession? Anything with our birthstone. May babies will love this octagonal-cut Green Onyx pendant necklace. Add to your favourite chain - or gift to someone special - for a super personal touch. 18k Gold Plated, Stainless Steel 6x4mm Octagonal cut Gemstone Green Onyx Green Onyx for strength and positivity and balance Chain length 16" (40.5cm), extends to 18" (45.5cm)