With rough diamonds everywhere this season, it’s not surprising designers are also recognizing the affordable charm of boulder opal. This cut combination of opal and its host rock matrix has the look of rough even when polished in an oval cabochon shape. It can look a little like an Easter egg, with a precious surprise inside. Fire opal in rough-but-smooth nugget shapes is also becoming popular. These rough but refined gems are always colorful and completely unique, giving even a pendant strung simply on a cord one-of-a-kind appeal. — Cheryl Kremkow