Opals are some of the most unique gemstones on Earth. They range from milky white to fiery red and deep blue-green, and all have a kaleidoscope of shimmering colors within, called play-of-color. Here ...

Gift 5 articles to anyone you choose each month when you subscribe. Thirty years ago, I didn’t like opals, they were a little ‘common’,” says Jacqueline Karachi, Cartier’s creative director of high ...