From Chopard to Piaget, brands are releasing colorful hard-stone dials that channel the flamboyant spirit of the era.

Compared to common opal, which is usually one color, black opal exhibits many different colors contrasted by a dark body tone. Frederick: It's simply the most stunning gemstone on the planet.

displayed internally a slight tinge of red like a spark of fire”—implying that Lady Hermione brought out the magic in the stone. The opal would change color depending on her mood. Later in the ...