Fireworks and Rainbows... Unlike any other gemstone, opal dazzles the eye with a spectral display of flashing and dancing colors – colors that move and shift within the opal’s mysterious depths. A Roman historian in the first century AD wrote, “There is in them a softer fire than the ruby, there is the brilliant purple of the amethyst and the sea green of the emerald – all shining together in incredible union. Some by their splendor rival the colors of the painters, others the flame of burning sulfur or of fire quickened by oil.” Opal offers the wearer a wider variety of appearances and color choices than any other gem.
Opal is treasured as much for its many different appearances as it is for its breathtaking beauty. There are over 100 different variety and trade names used today to describe opals. Opals with a lighter body color are often called white opals, and those with a darker (and more rare) body color are classified as black opals. Whether white or black, the value of an opal depends upon the vividness of the spectral flashes (often called play of color) visible from within the gem and the patterns these colors form. Another popular opal with little or no play of color is fire opal. Fire opals range in hue from vivid yellows to fiery reds and oranges.
Opal is the birthstone for October and shares this designation with tourmaline.
Most of the world’s opals come from the deserts of Australia. Other important sources include Mexico and the United States.
There are various treatments used to enhance the beauty of opals. The most common treatments darken the body color, making the play of color slightly more noticeable. Some opals are coated with oil, wax or plastic to improve their appearance. All of these treatments only affect a thin outer layer of the gem’s surface and, therefore, are not considered stable.
Because of their unusually high water content, opals should be protected from heat and strong light that can dry them out. Opals also draw moisture from the air and, therefore, should not be stored for long periods of time in dehumidified environments such as a bank vault. Never clean an opal using strong chemicals or detergents, and avoid both ultrasonic and steam cleaning machines. Because opals are slightly softer than most transparent gemstones, they are best suited for wear in earrings and pendants. When mounted in a ring or bracelet, special attention should be paid to ensure the stone is well protected. Opals can be cleaned with plain soap and warm water using a soft brush. Be sure to rinse and dry your jewelry thoroughly after cleaning.
Photo: Robert Weldon, Copyright Professional Jeweler Magazine
Editors Note: This article is © 2002-2011 Jewelers of America Inc.