Opals are stones with tiny crystalline spheres that seem to sparkle as they refract light. Precious opals are known for their “play of color.” While 95% of the world’s opals do not exhibit this play, many prize the precious varieties.
Opals exhibit an impressive color range. They can be milky white, pink, light green and blue, gray, or black. All precious opals are multi-colored, and the greater the variety of colors, the greater the value of the stone.
Quality of opals is evaluated through several different means. Since they are not clear gemstones, clarity matters less than with other stones. A major consideration is body tone, the main background color of the opal. Darker body tones fetch higher prices than light or white body tones.
The opal’s brilliance is classed as dull, subdued, bright or brilliant. The greater the degree to which the colors are brightly displayed, the better the quality. The pattern of colors in the opal is also assessed. The highest quality patterns are those in which the different colors are represented in equal proportions, called the harlequin. Any faults such as cracks, inconsistent coloring, or breaks in the pattern can reduce the value of an opal. A crack can render an the gem worthless, while pattern disruptions may merely reduce the price.
Prices for opals depend upon overall quality. Commercial stones may be less than 100 US dollars (USD). The highest valued gems, black with red, in the highest quality ratings can be extremely expensive. A single carat can cost as much as 8,000 USD.
Opals have been prized at least as far back as 6,000 years ago. Louis Leakey found artifacts in Kenya that dated back to 4000 B.C.E. Opals are valued by many cultures, and could be found in both the New World and the Old. Early deposits were likely mined in Egypt, but today’s opals are primarily obtained from Australia.
The Ancient Greeks developed a lovely theory about the development of opals. They were said to have fallen from heaven during flashes of lightening. Therefore, they were a byproduct of Zeus. Opals were linked with the ability to prophesy events, or at least to give the wearer a little foresight.
The Romans believed wearing these gems helped clarify emotional states and made wearers become more spontaneous. Like the Greeks, the Romans also credited the opal with providing clarity of thought and foresight. European nations during the Middle Ages watered this down somewhat, but felt that the gems had medicinal properties that would protect the eyes.
Negative connotations with opals began in the 18th century, when they were thought to be bad luck. However, Queen Victoria worked hard to defeat this “bad luck” theory when huge caches of opals were found in Australia. Today, some still feel that it is bad luck to purchase an opal for oneself, but good luck if someone else gives one to you.