Opal, the birth stone for October, is one of natures most prized gems. The gemstone, which also happens to be the recommended jewelry gift for 14th wedding anniversary, was mined by Eastern European, the Aztecs and ancient tribes of Central Africa. Opals have been featured in the crown of the Holy Roman Emperor and crown jewels of France. They were mentioned in the plays of Shakespeare and the novels of Sir Walter Scott. Napoleon gave an Opal to Josephine. Queen Victoria gave them out as wedding gifts.

One of the reasons this gem has been so revered is because of its supposed mystical powers. Scandinavian woman wore Opals in their hair to prevent it from going gray. The Arabs thought Opal would ward off lightning and grant invisibility to its wearer. Other powers ascribed to the gem include the ability to grant vigor, aid the heart and kidneys and protect against fainting and infection.

Worshipped by the Romans as a symbol of hop, fidelity, purity, and good luck. Opal is sometimes called the Queen of Gems because the gemstone can flash patterns of color representing every hue of the rainbow.

This play of color is one of Opals signature characteristics. The gem is found in a range of hues, including white Opal, the most common; black Opal; boulder Opal, black Opal with iron oxide; Crystal or water Opal, which transparent; and fire Opal, which has a yellow to orange to red body color.

The vast majority of the worlds Opal supply comes from Australia. Black Opal is the rarest variety and therefore the most valuable. White Opal is also mined in Brazil. Fire and crystal Opal can be found in the United States, Nevada, and Mexico.

Brilliance of color and color pattern are critical in determining the value of Opal. Opals with strong flashes of red fiire are generally the most prized. Stones with blue or green flashes are more common and subsequently less valuable. Stone size also helps determine price, since the gem is very rare in larger sizes. Prices can vary from a few Dollars per carat for common white Opal to more than $1000 per carat for fine Black Opal. Most stones are not faceted and usually cut into rounded cabochons to enhance color play.

Perfect natural Opals are extremely rare and expensive. Many are treated to enhance their appearance. One common technique is to place the Opal in a sugar solution and then in sulfuric acid, which blackens body color and makes the play of color more pronounced. Other treatments include applications of colorless oil, wax and resin, plastic, or synthetic resins and hardeners to fill cracks and improve durability.

With hardness of approximately 5.5 on the Mohs scale, Opal is relatively fragile, and care should be taken not to scratch, chip, or crack it. To clean Opal, use a soft cloth moistened with olive oil. Do not use chemical or mechanical cleaners. Also, avoid heat and dry conditions that dehydrate and crack the stone. Avoid impacts.