Opal is the product of seasonal rains that drenched dry ground in regions such as Australia’s semi-desert “outback.” The showers soaked deep into ancient underground rock, carrying dissolved silica (a compound of silicon and oxygen) downward. (http://www.gia.edu/opal)
During dry periods, much of the water evaporated, leaving solid deposits of silica in the cracks and between the layers of underground sedimentary rock. The silica deposits formed opal.
Precious Opals have unique rainbow colors this separates it from the other gems. The flashing rainbow colors are called play-of-color and without the flashing colors it’s called the common. The colors are beautiful and different.
Play-of-color occurs in precious opal because it’s made up of sub-microscopic spheres stacked in a grid-like pattern—like layers of Ping-Pong balls in a box. As the light waves travel between the spheres, the waves diffract, or bend. As they bend, they break up into the colors of the rainbow, called spectral colors. Play-of-color is the result. (http://www.gia.edu/opal)
During the Romans times they thought the precious opal was powerful. They (Bedouins) believed that precious opals had lightning stored in it and when there was a thunderstorm it fell from the sky. Australia’s mine had started producing the opals commercially in the 1890’s and it soon became the world’s primary source.
There are five categories of the gem:
White or light opal, Black opal, Fire opal, Boulder opal, and Crystal or water opal. Opals are usually sphere shapes but varies in size. Opal is considered an October birthstone and people use to think it was unlucky to wear opal if you were born in another month. I guess that goes for everyone in the world if they wore their birthstone in another month. Some people wear their birthstone all the time and never take it off.
Because of the different colors the gem was known as the luckiest and most magical stone. At one time it was thought to have the power to preserve the life and color of blond hair. Through out history everyone or every culture had its own myth. The Europeans considered the gem to symbolized hope, purity, and truth. While other cultures credited the opal with supernatural origins and powers.
The Romans named the stone opalus, which is a synonymous with “precious stone”. Even writers compared the gem to volcanoes, galaxies, and fireworks. I can understand comparing it to the fireworks but I know the opals are without colors. It seems as though to all cultures stones are precious in there own way.