4.40 Onyx & Diamond Spider Brooch 18k Yellow GoldThis 18 karat yellow gold spider brooch features a 4. 40 carat black onyx oval cabochon body measuring 14. 00 x 9. 85 x 4. 40mm and a . 07 carat round brilliant cut diamond head. The onyx displays the deep, opaque black color characteristic of the stone, with the cabochon cut's smooth, domed surface showing off its solid color. The diamond carries SI1 clarity and a G color grade. The gold legs extend from the onyx body in three dimensional detail,