Value of giant pearls lies in clams that make them

Most of my international e-mail is about sperm whales and giant clams. In those letters, readers rarely ask about the animals. Instead people pose financial and legal questions, about which I know almost nothing.Besides being big, beautiful and endangered species, sperm whales and giant clams don't seem to have much in common. But these two marine animals share another notable trait. Both occasionally grow tumors that people might, or might not, pay a lot of money for. Those tumors, of course, are ambergris and pearls.I'm using the term tumor loosely because most tumors are lumps of living cells with no physiological function. The cells in ambergris and pearls, however, are not alive after the animals secrete them, and the resulting masses do have a purpose. Both substances enclose foreign bodies that might otherwise impair the animals' health.In sperm whales the foreign objects are the hard beaks of squids, the whales' main food source. Usually these sharp mouth parts pass through the whale's digestive tract, but sometimes they accumulate. Then the whale's body produces a material that encases and breaks down the beaks, thus protecting the animal's intestinal lining.Sperm whales eventually defecate these buoyant masses, and they drift around the open ocean until they wash ashore.People who find ambergris get excited, some over the prospect of getting rich from it, and some simply from the thrill of finding a natural marine treasure.One of the latter is a former Honolulu firefighter who found a chunk of ambergris (confirmed by NOAA whale researchers) years ago on a Hawaii beach. He considered this a gift from the sea, and after he read my column about ambergris, he generously cut off a piece and gave it to me. That waxy wedge doesn't look like much to some people, but in my home it's a jewel that holds a place of honor. (Thank you, Roger.)Speaking of jewels, giant pearls also cause a lot of excitement among people who think the pearls are worth millions.Giant clams secrete a substance called nacre around foreign bodies that sometimes get through their filtering system. As a clam grows so does its pearl.Of course, there's a world of differences between natural pearls and ambergris, but one stands above all others: Sperm whales excrete their ambergris, but to get a pearl, you have to kill the clam.Another distinction is usefulness. Some perfume makers believe that perfume made with ambergris is better than that made with synthetics. The point is arguable, but I leave that to perfume experts.Where's the sense, though, in coveting enormous misshapen pearls? Spherical perfection is what makes pearls valuable as jewelry. Giant clam pearls look like grubby snowballs made by 2-year-olds. Large size in pearls is also prized, but 14 pounds seems a little heavy for a necklace.This 14-pounder is the largest pearl ever found (after killing a magnificent clam about 200 years old) and has brought deceit, violence and lawsuits to people who owned it, thought they owned it or wanted to own it. The highest price I've seen for this pearl, which might be wishful thinking, is $75 million.Maybe ambergris and giant pearls are valuable to certain people and legal to possess, and maybe they aren't. All I know is that I'm not the one to ask.Ask me about the animals that make them, though, and I'll work hard to find an answer.http://www.starbulletin.com/news/20100315_value_of_giant_pearls_lies_in_clams_that_make_them.html

Creating Cultured Pearls From The Queen Conch: Scientists Unlock Mystery

For more than 25 years, all attempts at culturing pearls from the queen conch (Strombus gigas) have been unsuccessful -- until now. For the first time, novel and proprietary seeding techniques to produce beaded (nucleated) and non-beaded cultured pearls from the queen conch have been developed by scientists from Florida Atlantic University's Harbor Branch Oceanographic Institute (HBOI).

With less than two years of research and experimentation, Drs. Héctor Acosta-Salmón and Megan Davis, co-inventors, have produced more than 200 cultured pearls using the techniques they developed. Prior to this breakthrough, no high-quality queen conch pearl had been cultured. This discovery opens up a unique opportunity to introduce a new gem to the industry. This significant accomplishment is comparable to that of the Japanese in the 1920s when they commercially applied the original pearl culture techniques developed for pearl oysters.

HBOI has been working with the Gemological Institute of America (GIA) to conduct extensive laboratory testing of the queen conch cultured pearls. In its independent analysis, GIA used techniques that included conventional gemological examination, chemical composition, spectroscopy, spectrometry and microscopy. HBOI and GIA plan to jointly publish the results of these trials in an upcoming issue of GIA's scientific journal, Gems & Gemology.

"This is a significant development for the pearl industry, and we were very excited to have the opportunity to closely examine these unique conch cultured pearls in our laboratory," said Tom Moses, senior vice president of the GIA Laboratory and Research. "Several of the pearls we examined are truly top-quality gems. With the equipment and expertise available at the GIA Laboratory, identification criteria are being compiled to separate queen conch cultured pearls from their natural counterparts."

Previous efforts to culture queen conch pearls were unsuccessful, probably because of the animal's sensitivity to traditional pearl seeding techniques and its complex shell. The spiral shape of the shell makes it virtually impossible to reach the gonad, one of the pearl-forming portions in pearl oysters, without endangering the animal's life.

"Perhaps the most significant outcome from our research is that the technique we have developed does not require sacrificing the conch in the process," said Davis. "The 100 percent survival rate of queen conch after seeding and the fact that it will produce another pearl after the first pearl is harvested will make this culturing process more efficient and environmentally sustainable for commercial application."

Survival of the animal is critical because commercial fishing has depleted the once-abundant wild populations of queen conch, and they are now considered a commercially threatened species in Florida and throughout the Caribbean.

There are basically two types of cultured pearls: nucleated (beaded) and non-nucleated (non-beaded). Nucleated cultured pearls are produced by inserting a piece of mantle tissue from a donor mollusk and a nucleus, usually a spherical piece of shell, into the body of a recipient mollusk. Non-nucleated pearls are produced by grafting only a piece or pieces of mantle tissue, and no bead is inserted.

"We used two different seeding techniques to induce pearl formation in the queen conch," said Acosta-Salmón. "One was a modification of the conventional technique used to produce cultured pearls in freshwater mussels, and the other was a modification of the conventional technique used in marine pearl oysters."

Conch pearls are formed by concentric layers of fibrous crystals, and this layering often produces the desired flame structure, which is characteristic of conch pearls. The pearls have a porcelain finish and luster like the interior of the conch shell, and come in a wide variety and combination of colors including white, red, pink, orange, yellow and brown. Queen conch pearls are measured in carats like traditional gemstones.

The size of the cultured pearls produced by Acosta-Salmón and Davis is controlled by the size of the bead and the culture time. The researchers have experimented with culture times from six months to two years; longer culture times may produce larger pearls. The queen conch is farmed in aquaculture tanks, and the queen conch cultured pearls in the initial harvest were grown in an aquaculture facility at HBOI. Queen conch achieve full size at about three years and have a life span of up to 40 years.

The queen conch is the largest molluscan gastropod of the six conch species found in the shallow seagrass beds of Florida, the Bahamas, Bermuda, the Caribbean Islands, and the northern coasts of Central and South America.

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Adapted from materials provided by Florida Atlantic University, via EurekAlert!, a service of AAAS.

Mother-of-pearl From Shells Could Inspire Regeneration of Human Bones

Researchers from the University of Granada, the Spanish National Research Council (CSIC) and the University of Aveiro (Portugal) have studied for the first time nacre's growing mechanism of gastropods, a first step for the artificial reproduction of this material in laboratories which could make possible its use in biomedicine, with applications such as the regeneration of human bones.This work has been recently published in the journal PNAS, and its authors are Antonio Checa, Professor of the department of Stratigraphy and Paleontology of the University of Granada; Julyan Cartwright, researcher of the Andalusian Institute of Earth Sciences (CSIC-UGR), and Marc-Georg Willinger (University of Aveiro, Portugal).Many molluscs present an iridescent nacre layer on the internal surface of their shells, which lends them an enormous strength against fractures. Oddly, although molluscs have been producing nacre for million years, men had not been able to reproduce it artificially.Apart from their beauty –this is the material pearls are made of-, scientists have also done research into nacre due to its biomedical applications and its excellent biomechanic properties. If it was possible to reproduce this natural compost in an artificial way, it would have multiple and relevant applications.Gastropods' nacreThe authors have analysed gastropods' nacre in detail (pleurotomariidae, turbos, trochus, abalones and others). Such nacre grows forming block towers, as piles of coins, unlike bivalves (nuculas, mussels, nacras, pearl oysters), which grow just like terraces of tablets. Nacre is made up of blocks of aragonite separated by membrans of polysaccharides and proteins, just like bricks and mortar in a wall.The nacre grows in terraces because it is limited by a membrane (superficial membrane) which covers and protects it from sea water when the animal goes into its shell. Such superficial membrane must carry out different tasks in order to permit the prodcution of nacre and therefore it is "a wonderfully complex structure", according to the authors of this work. This article has showed how the superficial membrane organizes nacre in towers and how mineral blocks are conected through a central column.Source: University of Granada