One of the world’s most coveted gemstones, opal’s name evolved from the Roman opalus which was derived from the Greek opallios, meaning “to see a change of color.” The Greek word was a modification of the ancient Indian Sanskrit name for opal, upala, which meant “precious stone.” Opal's unique qualities have attracted the attention of many ancient civilizations – and still do.
Opals possess flashes of rainbow colors that change with the angle of observation, called play of color.
|Ethiopian opals require different care than other opals due to their ability to absorb water. While it has been popularly considered a good idea to soak opals in water, this does nothing for an opal and in fact, should be avoided in the case of Ethiopian (Wollo) opals. If they do get wet, they will lose their play of color, becoming almost opaque. Not to worry – if allowed to dry in a normal environment, they will revert to their original appearance, usually within an hour, but this depends on size of the opal and humidity. For this reason, it is best to avoid dirty or colored water and even oils. Clean them with a dry, soft cloth. |
Opals should be protected from chemicals, high heat, and harsh wear. Because opals contain 5 to 10 percent water, some opal has been known to dry out and craze (small hairline cracks) after a short while or even after a lifetime of use in a piece of jewelry. Ideally they should not be stored in dry, air-tight containers like safe-deposit boxes. Opal jewelry should be cleaned with mild soapy water and a soft brush or cloth.
|Literally every color of the rainbow, be it their play of color or body color. Crystal opal has no body color, white opals are white – ideally with flashes of color within. As opals become increasingly dark, they are called dark opal until they become dark enough to be called black opal – the rarest of all opals. Beyond the black and white palette, there are fire opals with a body color ranging from colorless to yellow, orange and into vibrant reds, sometimes with play of color as well, but usually not. Fire opal is usually faceted to show its clarity. Peruvian opal is seen in translucent blues and greens as well as pink, and these are known as common opal because they never show a play of color. Another variety is the green prase opal that is similar to chrysoprase in color. Soft blue-gray colors are also seen. Ethiopian opal is hydrophane opal with unique properties. Hydrophane opal is opal, but can absorb water due to its molecular structure. This unique type of opal is seen in a variety of looks – some may look like fine crystal opals, other like fire opal. Natural Ethiopian black opals have been seen, but most are enhanced with smoke to give the look of black opal. Learn more. |
|While any play-of-color is welcome, opals displaying fire opal with all colors are the most prized by collectors. Lightning Ridge black opals are the most valuable among all opals. Crystal opals are also highly prized, as are the purer red shades of fire opal, known as cherry opal. The patterns seen are infinite in their variety and make each opal unique. Rare and unique patterns can add significantly to an opal's value.|
Name Origin and Meaning
The modern word for opal is probably derived from the Sanskrit upala meaning "valuable stone." Upala was likely the root of the Greek term opallios, which means “color change," or the Roman opalus, which means "precious stone." Mayas and Aztecs had a name for opal that meant "bird of paradise stone." Based upon these names, the flashy play-of-color in opals must have mystified the ancients just as it does us today.
Discovery and History
The discovery of opals is ancient and uncertain. It is believed that opals were first mined around 4000 B.C. in Ethiopia, but their popularity did not grow until the Romans embraced them around 100 B.C. By then, the majority of opals were mined in Hungary. For about 1,000 years, Hungary was the opal supplier of choice for European rulers and clergy.Precious opals were discovered in South Australia, Queensland, and New South Wales, Australia, around 1887. Rare black opals were found in the Lightning Ridge field in New South Wales in 1905. By the end of the 19th century, Australia had taken over as the world's primary source of precious opals.Mexican opal officially discovered around 1835, but known during Aztec period or earlier. Brazilian opals were discovered in the latter half of the 20th century, but the fire opal is a more recent discovery.
Ethiopian opal – “rediscovered” in 2002-2003 in Shewa Province. Made a big splash, but much of it proved unstable and the industry lost interest. In 2008, the Wollo area started producing and this material, once cut, is mostly quite stable.
An example of bad luck in an 1829 Sir Walter Scott novel led the public to believe that an opal had caused misfortune to befall the heroine. This reinforced an old idea that opals were bad luck, and the opal market dropped in the aftermath. Shortly after this time, Australian opals began appearing in the market, but dealers were hesitant because the Australian opals were so brilliant, some assumed they were fakes. Fortunately Queen Victoria fell in love with opals, and her passion for them helped restore opal's popularity.
Precious opals display play-of-color, a brilliant range of rainbow-like colors that sparkle when viewed from different angles. Only opals containing silica spheres in very precise arrangements and of a particular size display this rare effect, sometimes commonly referred to as "fire" or "flash". The physical structure of opal is unique. Tiny spheres of silicon form a neatly stacked structure interspersed with water. When these spheres are consistent and orderly in their arrangement, play of color will result. When disordered, there is no play of color and common opal or potch is the result. Play of color is the result of interference of the light as it travels through these layers of tiny spheres.
An Australian aborigine legend has a more romantic explanation of an opal's play-of-color, claiming that the colorful gems were born when the Creator's footprint touched the earth at the base of a rainbow.
Coober Pedy is a fascinating mine located in the South Australia desert. During their summer months (December through February), temperatures there can rise as high as 140F degrees. To survive the unbearable heat, miners build their homes in the cooler earth underground. As a result, the land around Coober Pedy looks like an abandoned moonscape, earning it a starring role as the setting for Mel Gibson’s Mad Max movie. Read more about opal.