Akoya cultured pearl farming in eastern Australia

Akoya cultured pearls have been produced on the eastern shoreline of Australia since approximately 1999 using Pinctada imbricata fucata mollusks native to New South Wales. Unlike many of their Japanese counterparts, Australian akoya cultured pearls are harvested after 18 months of growth and marketed without any post-harvest treatments involving dyes or bleaches. This study presents the first gemological and mineralogical characterization of Australian akoya cultured pearls using Raman, photoluminescence, FTIR, and UV-Vis specular reflectance spectroscopy. Raman and FTIR spectroscopy identified the major mineral phase aragonite as well as some organic compounds. While Raman spectroscopy revealed polyene-related pigments with bands occurring at 1134 and 1532 cm^–1, FTIR spectroscopy showed sulfate- and polysaccharide-associated groups occurring at around 1200 and 1115 cm^–1, respectively. UV-Vis spectroscopy revealed broad spectral features that provide insight into the distinct bodycolors and enable discrimination from some non-akoya saltwater cultured pearls from P. margaritifera, P. maxima, and P. mazatlanica bivalves, while separation from other untreated akoya pearls is not possible. Production processes are examined to better understand the modern, sustainable, and environmentally friendly pearl farming operations in Australia.