Irene Neuwirth. One-Of-A-Kind Emerald and Onyx Earrings. The mix of black and green in Irene Neuwirth’s one-of-a-kind emerald and onyx earrings makes for such a strong combination that it is hard not to take a second look. Strikingly bold, these baubles excite with the contrast of dark and light colors placing them into a realm all by themselves. One-Of-A-Kind. Set with Mixed-Shape Emeralds (11.07 CTS) 30 x 18 Black Onyx. 2MM Rose-Cut Diamonds (1.51 CTS) Pave Hook. 18K White Gold. Available in White Gold.