GemGeek
Pearlista
- Joined
- Sep 20, 2006
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From GIA's G&Gebrief:
Queen Conch Cultured Pearls: A New Gem
Natural conch pearls, especially those with attractive pink coloration and flame structure, have very limited availability in the jewelry market. For more than 25 years, attempts at culturing pearls from the queen conch (Strombus gigas) have been unsuccessful - until now. Scientists from Florida Atlantic University's Harbor Branch Oceanographic Institute (authors Acosta-Salm?n and Davis) have developed proprietary techniques to produce beaded and non-beaded cultured pearls from the queen conch.
The GIA Laboratory has examined more than 200 of these conch cultured pearls. The samples were spherical, oval, elongated oval, and irregular in shape, in sizes from about 1 mm to over 10 mm in longest dimension. They occurred in a wide variety of colors, including white, "cream," yellow, brown, pink, and red. More than 10% showed good luster and flame structure. The 0.51 ct non-beaded sample shown here is one of the highest-quality conch cultured pearls GIA examined.
Raman spectroscopy and scanning electron microscopy revealed that all the cultured pearls were composed of aragonite fibers in bundles with alternating orientations. This structure is identical to that seen in natural conch pearls. X-radiography clearly showed the beads or tissue-related cavities in the beaded and non-beaded samples, respectively. Based on these features and other gemological and spectroscopic properties, identification criteria are being compiled to separate the conch cultured pearls from their natural counterparts.
These queen conch cultured pearls represent a new gem for the jewelry industry.
- Wuyi Wang and Kenneth Scarratt
GIA New York and Bangkok
Queen Conch Cultured Pearls: A New Gem
Natural conch pearls, especially those with attractive pink coloration and flame structure, have very limited availability in the jewelry market. For more than 25 years, attempts at culturing pearls from the queen conch (Strombus gigas) have been unsuccessful - until now. Scientists from Florida Atlantic University's Harbor Branch Oceanographic Institute (authors Acosta-Salm?n and Davis) have developed proprietary techniques to produce beaded and non-beaded cultured pearls from the queen conch.
The GIA Laboratory has examined more than 200 of these conch cultured pearls. The samples were spherical, oval, elongated oval, and irregular in shape, in sizes from about 1 mm to over 10 mm in longest dimension. They occurred in a wide variety of colors, including white, "cream," yellow, brown, pink, and red. More than 10% showed good luster and flame structure. The 0.51 ct non-beaded sample shown here is one of the highest-quality conch cultured pearls GIA examined.
Raman spectroscopy and scanning electron microscopy revealed that all the cultured pearls were composed of aragonite fibers in bundles with alternating orientations. This structure is identical to that seen in natural conch pearls. X-radiography clearly showed the beads or tissue-related cavities in the beaded and non-beaded samples, respectively. Based on these features and other gemological and spectroscopic properties, identification criteria are being compiled to separate the conch cultured pearls from their natural counterparts.
These queen conch cultured pearls represent a new gem for the jewelry industry.
- Wuyi Wang and Kenneth Scarratt
GIA New York and Bangkok
