One of a kind reversible Opal necklace with the most rare of all Opals, black, on one side weighing 4.25 carats and a white Opal weighing 1.45 carats on the other. These Opals measure 14.5x10.6mm and 10.2x7.3mm. There are flashes of red, yellow, blue, green, pink, and orange that move as the light hits each of the gemstones. This comes with a 21” Sterling silver chain, other lengths are available. I’ve been involved in selling jewelry for decades and I’ve never seen another like it.