The Allure Of Opals}

The Allure of Opals

by

Geoguy

Opal is a form of silicon dioxide that has no definite crystalline structure, and yet is a popular and pretty gemstone for making silver pendants and other jewelry. It is an unusual gemstone in that most opals contain an appreciable amount of water. While the water content can be as high as thirty percent, most specimens have moisture contents in the range of 6 to 10 percent. This is a moderately soft gemstone, rating at 5.5 to 6.5 on the Mohs scale. Mohs scale has diamond which is the hardest substance known to man at a rating of 10, while the softest substance talc rates a 1. This is also a relatively light gem with specific gravity ranging from 2 to 2.5. Most opals are brittle and can be broken by a sharp blow of even moderate strength. Furthermore, they can be scratched quite easily. Depending the individual water contents, some opals can be irreversibly damaged if they lost their moisture by exposure to intense heat. As noted earlier, opals have an amorphous structure. They are generally made up of tiny spheres, with the voids filled by hydrated silica. If the stone has a random or disorderly arrangement of spheres, it is considered to be common opal.

Specimens with a structured arrangement of spheres are considered to be gem quality or precious opal. Precious opal generally has better optical properties and characteristics compared to common type. As expected, common opal is less expensive than the precious variety of the stone.

Opal jewelry is usually an important part of most jewelry collections. Earrings, bracelets and other jewelry with this gemstone are popular in todays fine and costume jewelry. However, most specimens have very light and mild colors, and are therefore often paired with other brightly colored stones such as rubies, diamonds, and sapphires. Rarely are opals included in freshwater white pearl necklaces. Occasionally, a small amount of gemstone beads may be included in a string of dark colored pearls.

Historically, ancient Romans in particular were very fond of this gemstone. One emperor offered a third of his vast fortune and empire for a single stone. Roman Senator Nonius risked banishment by Marc Antony rather than part with a beautiful opal that he owned. The Romans believed that opal symbolized hope and that a tiny rainbow was at the heart of each stone. Ancient civilizations of the Middle East that the fiery colors of opal resulted when the stone was created in heaven and fell to the earth in bolts of lightening.

Larry has authored numerous articles on

sterling silver pendants

and other silver jewelry. He has also written on

cultured pearl necklaces

and on consumer electronics including

cheap MP3 players

.

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The Allure of Opals}