Sunday, September 27, 2009

October Birthstone - Opal

A new month is almost upon us (I can't believe how fast this year has flown by!) and it's time for a discussion of the birthstone for the month of October - the opal. (Tourmaline is also considered a birthstone for the month of October, but more charts mention Opal, so I will discuss this gemstone first.) The opal is also the gemstone for the 13th wedding anniversary.

The opal has often been called the "Queen of Gemstones." It takes its name from the Latin word upala, which means precious stone. This fabulous gemstone has flashes of rainbow-like colors when it is viewed from different angles. This color is created by silica spheres which are contained within the opal.

There are two types of opals - precious and common. The method in which the silica particles form determines the type of opal. Precious oplas have silica particles packed in rows and layers which causes iridescent flashes of color, sometimes referred to as "fire." The common opal lacks this play of light. Black opals are considered the rarest of opals and are just full of fire and color.

Opals have been mined in various locations around the world but, by far, the largest deposits have been found in Australia - with 95% of the world's opals originating there. Other sources of mines include Mexico, Africa, the US, Brazil, parts of the old Soviet Union and a few other areas in South America.

The hardness of opals vary, but they generally range from 5.5 to 6.5 on the Moh's scale of hardness. The gemstone has a chemical formula similar to quartz with the addition of 5 to 10 percent water. This quantity of water for the optimal play of color. Old time miners often used to store their opals in water, thinking this would preserve the color.

Be aware when buying opals that the gemstones are not always whole single stones. Many opals sold are actually doublets or triplets. These are composite stones which are made by positioning a thin layer of opal on top of a layer of glass or less expensive gemstone. To determine this, inspect the sides of the opal, and look for indications that it is a stack of layers. In this case, you have a composite, not a whole stone. You can also see if the stones base matches the top. If it doesn't, it may be composite.
There are many large opals. The Smithsonian is the home of the largest black opal, found in the Royal peacock mines in Australia. The record for the largest opal ever discovered reputedly goes to the "Olympic Australis", found in 1956 at the famous Eight Mile opal field in Coober Pedy, South Australia. It was found at a depth of 30 feet and named in honor of the Olympic games, being held in Melbourne at the time.

Photo credit Opals Down under

This extraordinary opal consists of 99% gem opal with an even colour throughout the stone. It is one of the largest and most valuable opals ever found. It was valued at $2,500,000 Australian dollars in 2005.

There is a great deal of legend, rumor, and folklore attached to the opal. One long standing rumor (as evidenced by the miners mentioned above) is that boulder opals will absorb water. In fact, opals must be treated with extreme temperature change to alter the water content of them.

The Aborigines believe that opals have lived in Australia since the beginning of time. Arabs think that opals fell from heaven as flashes of lightning, and Ancient Greeks believe that opals had the power to give the wearer prophecy and foresight.

For centuries, people have believed in the healing power of opals. They are thought to help with depression and to enable the wearer to find true love and happiness. Some believe that they enhance the positive qualities of those born under the signs of Cancer, Aries and Scorpio.

The care of opals is relatively easy. One of the main things that you can do to preserve your opal is to simply wear it! If exposed to heat (in storage) over a long time, fissures can develop and the color can become dulled. Wearing your opal will give it the humidity it needs to keep its color bright and vibrant.

To clean an opal, just use lukewarm water and a soft cloth. Some jewelers recommend using vinegar in the water. Be sure to dry it thoroughly after cleaning. Do not use harsh cleansers on your opals and do not clean opals with ultrasonic cleaners. Never rub oil on an opal. This may temporarily make the fire brighter, but it can also damage the opal.

Finally, an ode to the opal in this Georgian poem:

“October’s child is born for woe,
And life’s vicissitudes must know,
But lay an opal on her breast,
And hope will lull those woes to rest.”
Are you an October baby? What a lovely gemstone to have as yours!

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