Desirable antique Art Deco diamond ring, of French origin An item that would certainly not look out of place by members of the cast wearing Downton Abbey jewellery. Thanks to the hugely popular tv programme Downton Abbey, Art Deco Jewellery has become more desirable than ever, so it is with great delight I offer this amazing, original, Art Deco diamond ring for sale. Four large rose cut diamonds, surrounded by 32 smaller diamonds totaling approximately 4 cts.