The Poison Ring (Cushion onyx) KR 3.800,00 The poison ring is quite unique with a hidden room under the table top enabling the owner to store a picture of a dear one or a secret message. The ring is made of 925 sterling silver with a black diamond on the side of the ring (1.3mm) and black, matted onyx on top. The top plate comes in one size (16 x 18 mm). The signet rings will be available in the traditional ring size of 52-66 (unisex). See our size chart.