Opal was said to have all magic powers due to its many play of colors. Pliny wrote " In the opal, you see the living fire of ruby, the glorious purple of Amethyst, the seagreen of emerald, all glittering together in an incredible mixture of light." Opal gets its name from the Latin word meaning precious stones. The romans believed opal to be the symbol of hope and purity. Arabs believed that opals acquired their color from flashes of lightning. Opals also supposely guarded the color and life of blond hair.
Opal is the birthstone for October, alternating with Pink Tourmaline. The most highly prized opals contain multiple colors, called play-of-color. The play-of-color is caused by interference and diffraction of light set up by microspheres of silica. The range of color usually depends on the spheres, or the distance between the rows of spheres. The most desirable play-of- color is red. Spheres that produce red will also produce other colors, while spheres that produce the most common colors in opal, blue and green will only produce blue and green. Opals have a hardness of 5.5-6.5 on the Moh's scale. Opals usually have a water content of 3 -10%. To preserve their beauty, opals must be treated with care. It is important to keep opals away from heat and all chemicals and solutions. If an opal looses it's moisture, it may form cracks called crazing. Australia is the most important opal source. |
