The most valuable black opal features bright red stone against a very black base. In the '80s and '90s, gem-quality brown diamonds were worth about $1,500 per carat, but now many sell for up to $ ...

Adding to the ensemble’s allure, Radhika adorned her neck with a rare blue opal necklace surrounded by diamonds, designed by Lorraine Schwartz. This necklace held deep personal significance ...