Frozen tears of the gods
By Marcella S. Kreiter
CHICAGO, (UPI) -- The pearl necklace JoeDiMaggio gave Marilyn Monroe was within yards of the one MaryQueen of Scots wore before she lost her head in 1587.
La Peregrina, a famous necklace that oncebelonged to Spain's King Ferdinand and eventually was given byRichard Burton to Liz Taylor as a Valentine gift was in a casenearby.
Then there's a replica of a 14-pound pearlthe shape and size of a football perched inside a real 4 1/2 footwide giant clamshell.
All are among the 500,000 lustrous gemscollected to create the largest pearl exhibit ever put together.It opens Friday at the Field Museum of Natural History.
Pearls, sometimes called the frozen tearsof gods, are produced by hundreds of species of mollusks, 300freshwater varieties native to North America alone. Pearls varyin size, color and value and each can take anywhere from two to20 years to grow.
"Pearls have this beauty, symbolizingnot only innocence, purity and perfection but pride, prestige,vainglory and power," said Ben Bronson, co-curator of theexhibit and curator of Asian archaeology and ethnology at themuseum.
Exhibit co-curator Rudiger Bieler, chairmanof the museum's zoology department, said Scottish pearls are believedthe reason behind Caesar's decision to invade Britain and wasat the top of Queen Isabella's list when she sent ChristopherColumbus off on his voyage.
Most people associate pearls with oystersbut actually any mollusk that produces a shell can create them.Contrary to popular belief, natural pearls are not formed whena mollusk ingests a grain of sand, rather they more commonly areformed when a mollusk cannot rid itself of an irritating pieceof food or when a predator attempts to burrow inside the shell.The mollusk excretes alternating layers of aragonite, a form ofcalcium carbonate, and conchiolin, an organic material, to isolatethe irritant, applying multiple layers until the irritant is completelycovered and expelled.
Pearls, the only gems produced by a livingorganism, were once more highly valued than diamonds and rubies.
"Most of the pearls we know as gemscome from a small set of marine and freshwater mollusks, pearloysters and pearl mussels," Bieler said. "But really,any mollusk that has a shell -- abalone and conchs, even landsnails and chambered nautilus -- can theoretically produce a pearl.
"Pearl formation is really just anextension of shell formation."
Most cultured pearls are produced by insertinga bead into a pearl mussel. More often than not, these beads aremade from the shell of the North American freshwater mussel, whichlong provided material for the button industry but is currentlybeing threatened by habitat destruction, dredging and damming,as well as declining water quality.
Of the 300 native North American species,35 have become extinct in the last 50 years, 60 others are endangeredand there is concern about 50 more.
The modern technique for culturing pearlswas pioneered by 18th century Swedish botanist Carl von Linne,who created the first round cultured pearl by inserting a beadattached to a stick. The Chinese first cultured pearls in thefifth century by inserting small objects like a tiny Buddha intoa freshwater pearl mussel.
For centuries though, divers would plungeas far as 30 meters under water to gather basketsful of oystersto search for pearls.
"Pearls were gathered by slaves andsocial outcasts, people who were forced into it by poverty orby their masters," Bronson said.
The idea for the exhibit was hatched morethan four years ago over a bottle of wine during a trip to NewYork by Bieler to meet with colleagues from the American Museumof Natural History, who helped create the display.
"By the time we emptied the bottle,we had outlined a joint exhibit that would use the combined strengthsof our institutions -- bringing together biology, anthropology,mineralogy and paleontology -- to tell the story of pearls andmollusks that produce them," he said.
Bieler was really excited showing off a200-year-old necklace he convinced the German government to lendthe museum. The Royal Saxon necklace was commissioned by Augustthe Strong, who ordered the best 177 pearls collected over morethan a century from the White Elster River by generations of speciallyappointed harvesters be strung together in a necklace.
The exhibit runs through Jan. 5.