In Twelfth Night Shakespeare referred to opal as "the queen of gems." The Roman historian Pliny described it as having "the fire of the carbuncle, the brilliant purple of the amethyst and the sea green color of the emerald, all shining together in incredible union." The Romans considered opal a symbol of hope, an appropriate attribute for a gem with a rainbow locked within it. The Arabs believed opals fell from heaven in flashes of lightning, thus acquiring their fiery colors. These romantic notions are inspired by one of the most uniquely beautiful gemstones nature has ever produced-the dramatic, mysterious opal. The phenomenon displayed by opal is called play of color. It is caused by the diffraction of light set up by the layers of silica spheres in its composition. The effect is similar to the rainbow colors displayed on a soap bubble, only much more dramatic.
In the 19th century opal acquired a stigma through its role in the plot of a novel by Sir Walter Scott, Anne of Geierstein. The heroine owned an opal that burned fiery red when she was angry and turned ashen grey upon her death. Queen Victoria finally dispelled the curse by giving opal jewelry wedding presents to her relatives.
The most treasured variety of opal is black opal with strong play of color, that is, brilliant flashes of different colors. Black opal is so called because of its dark background color. The variety known as white opal has a light background, and the colors displayed lean toward the pastel hues.
Crystal opal has a colorless background and exhibits play of color, but, unlike white or black opal, it lets light pass through it.
Fire opal is also fairly transparent, but its background color may be yellow, orange, red or brown. Sometimes it doesn't even have the typical play of color. It's often called Mexican opal because Mexico is a major source of this type. Fire opal with a red body color is also known as cherry opal.
Opal that is colorless, transparent to semitransparent and has little or no play of color is called jelly or water opal.
Opal quality is judged by the number of colors exhibited and the evenness of the pattern.
Australia is the world's most important source of opal. The opal miner is a strange breed of individual. He chooses to lead a spartan life in a particularly barren and dry corner of the world while he searches for his rainbows. To escape the extreme temperatures, he must burrow a home underground. Opals are usually found in sandstone or claystone. Deposits are spread over a wide area, and there is little clue to their location. Mining is done on a small scale with hand-operated machinery and small tools. A pocket knife might be the final instrument to loosen an opal from its host rock.
Man Mimicking Nature
Over the past century scientists have become highly skilled at creating laboratory facsimiles of fine gemstones. Far from being mere look-alikes, these synthetic gems are made of exactly the same material that nature uses and mimic the natural structure perfectly. Synthetic opal first came on the market in 1974 and has been improving ever since. A skilled gemologist like a member of the American Gem Society can distinguish it from natural opal by viewing it under magnification, but to the untrained eye it looks natural.
The Versatile Opal
Because opal displays a whole rainbow of colors, it can be worn with any color outfit. It is usually cut in a dome shape and set in rings, earrings, pendants, bracelets and pins. It may be joined by accents of ruby, sapphire or emerald to enhance particular color flashes in the gemstone. A fine opal piece is often guarded in a web of small diamonds as are other exceptional colored gems. Some opals are fashioned into beads for a major contribution to a woman's total look.
Making a Wise Purchase
Since subtle differences in quality can make large differences in beauty (and price), it is important to select your jewelry from a professional who can guide you honestly and ethically in your purchase. Our firm is a member of the American Gem Society. As a condition of membership, we are re-examined each year to meet the Society's high standards for knowledge, professionalism and integrity. The AGS symbol is the hallmark of consumer protection within the jewelry profession - as it has been for over 50 years. Many gems are processed to enhance their natural beauty. Ask your American Gem Society jeweler to discuss which techniques might apply to the gem of your choice.