opal

1.47-ct Barion emerald-cut opal, Lambina Mines, Australia. © Dan Stair Custom Gemstones. Used with permission.

Resin opal. Photo by Aisha Brown. Licensed under CC By-SA 2.0.

Prase opals. Photo by Aisha Brown. Licensed under CC By-SA 2.0.

Gold opal. Photo by Aisha Brown. Licensed under CC By-SA 2.0.

Opal ring. Photo by Gyulfox. Public Domain.

Blue opal, 4.30 cts, Oregon, cushion cut, 10.8 x 11.2 mm. © The Gem Trader. Used with permission.

78 opal cabochons from Welo, Ethiopia (52 ctw) in 18k gold bracelet. © Rob Lavinsky, www.iRocks.com. Used with permission.

14k gold pendant with 31-ct crystal opal. Photo by Dan Mekis, Red Carpet Opals. Licensed under CC By-SA 3.0.

Layered boulder opal, about 3 cm in width. Photo by Dietmar Down Under. Licensed under CC By 2.0.