Gold Vermeil Siren Medium Stacking Ring. Blue Lace Agate. size M Currently on website for $150. The organic oval shaped aquamarine gemstone in this ring measures 12mm x 10mm and is rose cut to bring out the translucent, ocean-like colour and natural cloudiness that makes every piece entirely unique. Stack with other colour gemstones and diamonds for an eclectic, individual look. Please note that the colour and translucency of the aquamarine differs from piece to piece due to natural variation,