Brain Shaped Pearl for Auction at Bonhams

A 5lb (2.25kg) pearl, dubbed the ‘Palawan Princess’, the second largest pearl ever discovered, valued at as much as £250,000 is set to go under the hammer at Bonhams auction of Natural History in Los Angeles on December 6, 2009.

Palawan PrincessThe pearl measures six inches in diameter and bears an uncanny resemblance to a human brain. The pearl is accompanied by the lower half of the original giant clam shell showing where the pearl formed.

According to Mitch Jacubovic, the director of gemologists at the European Gem Laboratories USA in New York: “This is an once-in-a-lifetime look at one of nature’s most unique treasures. A pearl this size is not only one of the largest ones we’ve ever seen, it is among the largest pearls ever seen anywhere.” David Bidwell, a senior appraiser with Universal Gemological Services, called it “clearly one of the most valuable pearls of its kind in the world today.”

The Tridacna gigas was first described by Lamarck in 1758, and is known as the true “Giant Clam”. Reaching lengths of greater than 4 ½ feet (1.4 meters) and weighing hundreds of pounds, they can live well past 50 years of age. This is the largest species of bivalve mollusk to have ever lived in the fossil record of our planet. They can still be found in the waters of the Pacific stretching from the Philippines to Micronesia.

Almost any shelled mollusk can, by natural processes, produce some kind of “pearl” when an irritating microscopic object becomes trapped within the mollusk’s mantle folds and the conditions are correct. Interestingly, not all “pearls” are made of nacre, that combination of aragonite (calcium carbonate and conchiolin that is secreted from a mollusk and layered together to form what gemologists call a “nacreous” pearl. Some marine animals—namely snails and clams—produce gorgeous gems made up of non-nacreous calcium carbonate. Calcite, rather than aragonite is the primary material here and they are, thus, technically classified as calcareous concretions. A pearl that is not “mother-of-pearl”, might best be qualified “porcellaneous.” It indeed possesses a brilliant luster like porcelain, a hard resistant appearance, and occurs in a variety of colors according to the species producing it.

The Palawan Princess, a rare and immense natural non-nacreous pearl is a highlight of the unmounted gem section of the sale. The product of the giant clam shell Tridacna gigas it was found off the coastal waters of the Philippines.

www.bonhams.com/natural

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