Platinum 3.85ct Jadeite Cabochon Diamond box chain necklace 5.4g JR8900

Fine Platinum Jadeite diamond necklace. One oval cut Jadeite cabochon, approx. 11.6 x 9.5 x 4.5mm halo set by natural round brilliant diamond, weight 0.28ct, F-G color/VS1-VS2 clarity. Hanging length is 7 8/" x 1/2", it suspends along an 17.5" Platinum 850 box chain. The pendant hallmark PT900, 0.28. Combine weight 5.4g.