Opal

October’s Opalescence

by Debbie Yonick

Bursting with life and vitality, the dazzling, hypnotic play-of-color that is opal inspires its moniker, Queen of All Gems, as it captures a rainbow in one stone.

The ancient naturalist known as Pliny the Elder, during the first century A.D., described opal as containing the glories of the most precious gems—the gentle fire of ruby, the rich purple of amethyst, the deep blue of sapphire, and the sea-green of emerald, all shining together in an indescribable union.

Throughout history this chameleon gem has symbolized good fortune and was believed to inspire love and creativity, enhance self-confidence, and ease navigating life changes. October’s birthstone, opal is a gem of positive transformation, revealing the colorful attributes of those who wear it. Magical, mysterious, and lively—opal is captivating new admirers with its variety.

“The major fashion houses in Paris have really been pushing opal in recent years, influencing designers worldwide to design with the most alluring gem on the planet,” hails Andrew Cody of Cody Opal, Melbourne, Australia. “There are no boundaries in working with opal. You can look into it and see a beautiful landscape. Each stone has a mystery that encourages curiosity.”

Opal is not a new phenomenon, says Jürgen Schütz of Emil Weis Idar-Oberstein, Germany, noting that gem houses like his own have been surviving on this gem for more than a century. “Opal has never really been out of fashion, but certainly when major jewelry brands, bespoke designers, celebrities on the red carpet, and the global press are showing more opal, everyone is talking about it.”

Striking examples spied on recent red carpets include dramatic drop earrings with Bryce Dallas Howard in fire opals and Melissa Benoist in pink opals with peach moonstones at the Golden Globes, and America Ferrera in boulder opal with turquoise at the Oscars—by Los Angeles designer Irene Neuwirth. Angela Bassett also rocked the Emmys in earrings with four tiers of Ethiopian opal drops totaling 20 carats in 18K rose gold with diamonds by Sutra, Houston, Texas.

^{1. Bryce Dallas at the Golden Globes 2016 wearing spectacular opal earrings. 2. Erica Courtney fire opal earrings with sherry pink spinels. 3. Erica Courtney's exquisitely combined fire opal and paraiba earrings. 4. Stunning 143ct boulder opal courtesy of Emil Weis.}

The not-so-romantic description of opal is hydrated silicon dioxide. Basically opal is made up of water and silica (the main component in glass). It contains anywhere from about 3% to 20% of water in its silica structure.

Precious opal, which shows play of color, is composed of minute uniform spheres of silica that are arranged together in an orderly three-dimensional grid, says Cody. “The spaces between these [light diffracting] spheres contain silica in solution. But in common opal, where there is no play of color, the spheres are of varying sizes and are not uniformly stacked.”

Ranging from semi-transparent to opaque, opal occurs in several types: White opal, the most common, has a transparent or white body color with vibrant pastel flashes of rainbow color. Black opal, regarded as king of the opal world, has a blue, gray or black body color that reveals a more dramatic play of color. Boulder opal is most often black opal with some of the ironstone matrix in which it occurred still intact—and has become quite a designer favorite. Crystal opal is transparent or semi-transparent dark to light body tone with brilliant flashes of color swimming within it. Fire opal is transparent or translucent with yellow to light orange to intense bright red body color that may or may not have play of color.

Schütz notes that fire opal, found in cavities and cracks of volcanic deposits, owes its unique color and brilliance to traces of iron oxide. Fire opals with no play of color are mostly faceted to optimize brilliance, he says, which is rather uncommon for opal that is typically cut in cabochons, sometimes beads. He says freeform shapes in the clear play of color goods have been very popular with designers looking for organic, natural, unusual pieces, as well as drop pairs for earrings in different opal varieties.

Factors determining the value of an opal, says Cody, include type (with black opal commending the highest price), brilliance, body tone (with black body color more valuable than gray or light with all other factors equal), transparency, pattern (with broad patterns and large flashes most desirable), dominant diffracted colors, thickness of color bar, and shape.

About 95% of the world’s opal is mined in Australia, with black opal from New South Wales, boulder opal (boulder matrix, opal nuts) from Queensland, and light opal (crystal, white, jelly) from South Australia. White opal is also produced in Brazil. Fire and crystal opal is found in Mexico and the United States. And since 2008, Ethiopia is proving to be a boon for the opal market with stable production, mostly white and crystal, a majority of which boasts vivid play-of-color. And, a recent deposit is yielding dark to black opal.

^{1. 22K boulder opal earrings by Margery Hirschey. 2. Exotic 14ct black boulder opal and diamond ring by Alishan. 3. Delicate opal ring by Alishan. 4. Exquisite opal collection from Cody Opal.}

Some opal types can be treated to enhance appearance. A common technique is to immerse white, gray or black opal in a sugar solution, then in strong sulfuric acid. The acid carbonizes with the sugar, leaving microscopic carbon specks that effectively blacken the body color, making the flashes of fire stand out. Some opals are also impregnated with colorless oil, wax, resin, plastic, and hardeners to hide crazing or improve durability. Fire opal is not commonly enhanced.

Natural opals are also found in composite or assembled stones called doublets or triplets. While they resemble black opal, they’re composed of a thin layer or two of white opal adhered to lower grade opal or another substance with black cement. Doublets are usually more expensive than triplets because more opal is used. Both types are sold by the stone rather than weight and are cut to standard millimeter dimensions. Cody advises against submersing composite opals in water or detergents that could deteriorate glues used to cement the lamination.

Opal ranks 5-6.5 on the Mohs scale of hardness, making this gem best suited for jewelry like earrings, pendants and brooches that rarely encounter impacts. In rings, a bezel setting helps to protect the stone. Generally a stable material, high heat or sudden temperature changes could cause it to fracture. To clean opal, use a soft dry or damp cloth. Do not soak it or use mechanical cleaners or chemicals. Get disclosure and care information in writing.

“Opal is a one-of-a-kind stone, very individual, for well-thought out designs where the gem is the priority,” hails designer Alishan Halebian, Tustin, California. “You never find one repeating another, and that’s what’s most attractive.” He notes that understanding the characteristics of opal is very important to determining what type to work with and how to use it.

Bespoke designers fancy using boulder opal. Halebian adores it for its “grainy” organic texture in gem mixed with matrix. While designer Margery Hirschey from Boulder, Colorado is partial to its aqua hues. She likens the artistic appeal to having a bunch of colors of paint on one brushstroke. “It’s like an Impressionist painting. I’m always looking for stones that have more than one hue in them.”

Also a fan of boulder but loving all types, Los Angeles designer Pamela Froman enjoys mixing opals with other gems like paraiba tourmaline and tanzanite, even rose quartz. “Opal is one of my favorite stones to work with; each one has a unique look and color way. I get so excited to design with them.”

^{1. America Ferrera at the 2015 Oscars donning Irene Newirth opal earrings.2. Irene Newirth opal and turquoise earrings. 3. Pamela Froman opal arabesque earrings. 4. Stunning 22K opal ring group by Margery Hirschey. 5. Fabulous opal specimen courtesy of Emil Weiss.}