Rainbow Moonstone Sphere. Orissa, India

With brilliant flashes of blue in the white moonstone, showing some black matrix, this is sphere originates from a locality known for its gem and massive moonstone deposits. Diameter 2 1/2in. Sold for $120 (Copyright © 2002-2008 Bonhams 1793 Ltd., Images and Text All Rights Reserved)

Moonstone owes its name to the white, almost magical shimmer that resembles moonshine. Blue-whitish light glides over the surface when the stone is cut cabochon. Gemologists call this phenomena adularescence, which originates from the interior structure of the gemstone in scales or lamellas. Incoming rays of light are refracted inside the stone and scattered, creating a unique play of light, which makes Moonstone so special and coveted. Moonstone is the most well known potassium feldspar of the orthoclase species. A combination of orthoclase and albite arranged in layers cause the lovely sheen. Moonstone is fairly soft, 6-6.5 (Mohs scale) and sensitive to pressure.

In Arab countries women often sew moonstone into their garments, because it's considered a symbol of fertility.

Moonstone is the birthstone for those who are born in June.

In Antiquity, as well as in the Middle Ages people believed that the cosmos is reflected in gemstones. The moonstone is assigned to the planets Neptune and Venus. The esoteric movement revived the ancient belief and the gem industry made it another marketing tool to promote certain gems.

This gemstone was extremely popular in the times of "Art Nouveau", more than 100 years ago. It used to decorate a striking amount of pieces of jewelry created by the famous French master-goldsmith René Lalique and his contemporaries. These pieces are usually only found in a museum or in safeguarded collections. .

The healing powers of gems remain a controversial issue, but are mentioned for centuries by healers, shamans and medicine men. Whether it's a fact or a placebo effect doesn't matter, if it helps. The safest approach is to wear the gemstone in skin contact to the troubled part of the body. Moonstone is said to be of help for headaches and backache. (source www.gemselect.com)

Bonhams. Natural History, 22 Jun 2008. 220 San Bruno Street, San Francisco // 7601 Sunset Blvd., Los Angeles. www.bonhams.com