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One of the oldest stones in circulation, opal has always been regarded as a beautiful gift from the gods. Said to have been created by the rainbow itself, opals reflect the very elements, from the fiery reds of the sunset to the deep blues of the skies and oceans. Each opal shares only one thing in common with another: its ability to shine and dazzle in an array of various colors.
Derived from the Sanskrit word "Upala", meaning valuable stone, the opal's name changed throughout the ages. The Greeks called it "Opallios", meaning color change. Finally, the Romans named it "Opalus", meaning stone from several different elements.
What made opals so interesting was that up until the 1960's, no one understood why the stones reflected so many different colors. During the 1960's, Australian scientists used an electron microscope to discover that rather than being made up of complex crystal structure, the inside of the opal was compacted spheres of silica that reflected the light, creating the various colors of the rainbow through reflection and refraction.
Ninety-five percent of opals are found in Australia. The remaining five percent can be found sporadically in Brazil, Mexico, and even in such states as Idaho and Nevada.
Opal is a very personal stone due to its fragile nature. Being two to six percent water, the stone requires that it be worn frequently, to acquire the necessary humidity from the air as well as from the skin. Therefore, it is not a good idea to keep these stones in dry, hot places, or else cracks and fissures will appear within the stone and it will lose its brilliance. Likewise, due to its relatively modest rating on the Mohs scale (5-6), the wearer should encase the stone in a clear resin, or find another way to keep the stone safe from tarnish and scratches when not in use.
The value of an opal is determined by rareness, size, color and other basic attributes that define a good gem. However, unlike most gems, “play of color” is highly important when measuring the quality of an opal.
Black, gray, crystal and Mexican Fire are the four most expensive and luxurious categories of opal. With these colors as a base, the reflections in an opal are brilliant and vibrant; the deeper the core color (black, gray, etc.), the more luminous the reflecting colors. For their wearer, opals reflect emotion itself. Said to aid in calming its wearer, opal will help dissolve depression, as well as help find true and lasting love. One of October's birthstones, it is guaranteed to not only be a great anniversary gift, but truly a gift of emotion.
Opal is a "living" stone, which means it must be protected from heat and detergents that "dry" the gem. Opals develop crazing if they are allowed to dry out. Heat treatment is catastrophic!! In addition to cracking, loss of water causes loss of iridescence. Care must be taken when polishing and setting opals. Despite their hardness, they are prone to crazing and cracking, and loss of water content causes a noticeable loss of iridescence. To prevent this, opals are normally stored in moist cotton wool or cloth until it is time to work with them. Sometimes, an opal that has lost its opalescence may be "rejuvenated" by rehydrating the stone with water or special oils, but this may only temporarily improve the stone's appearance.