This is one of the most vibrant black opals we have ever seen. Its electric green fire can be seen from space. Ok, not really. But it is truly captivating, and more than holds its own next to brilliant white diamonds.

• 8.4 x 7 mm natural black opal, 1.38 ct, Australia

• matched diamonds, 0.30 tcw, F/VS, Canada

• 18k and 22k gold

• 4 mm wide oak-bark band

• size 7