Professional Jeweler Archive: Sizing Up Pearls

March 2001

Gemstones & Pearls/Gemology


Sizing Up Pearls

Technological advances spur growth rate of cultured black pearls


Biotechnology has finally arrived on the gem scene. By inserting a time-release capsule filled with a secret and patented biotech agent in a Pinctada Margaretifera oyster during nucleation, researchers can enhance the growth rate and size of cultured black pearls.

The growth enhancer, created by BioPacific Development Inc., San Francisco, CA, is expected to help other pearl culturing methods as well, including Japanese akoyas South Sea pearls and Chinese freshwater pearls. BioPacific, a privately held company, hopes to sell its patents on the technology.

The growth enhancer reportedly is easy to administer and its cost is described as minimal. “It is nothing short of a revolution,” says Fred Ward, author of a series of gemstone books, including Pearls (Gem Book Publishers, Bethesda, MD). Ward, who is BioPacific’s spokesperson for the growth enhancer, likens the new technology to the development of the pearl culturing process a century ago.

The capsules deliver controlled dosages of growth enhancer throughout nucleation, resulting in several benefits for the oyster and the pearl:

For the Oyster

  • Shell size increases up to 22% over oysters not treated with the growth enhancer.
  • Shell growth occurs over a shorter time.
  • Metabolic rates increase by 30%.
  • Survival rates remain unchanged.
  • Nucleus retention rates remain unchanged.

For the Pearls

  • A pearl can be produced faster than one of comparable size without the growth enhancer.
  • Nacre deposition (in grams) increases by up to 36% in six months.
  • Quality characteristics (luster, shape, surface and color) are unchanged.

For the Pocketbook

The biggest benefit of all, Ward says, is the substantial increase in gross revenue allowed by using the growth enhancer. “A typical Margaretifera or Maxima pearl is 10mm-11mm in diameter. Typically, a nucleus of 6.5mm or larger is implanted to get pearls of this size. If the resulting pearl is 10.5mm, the pearl has about 4.0+mm of total nacre, as measured by the increased diameter of the pearl. (2mm of nacre on each side of the bead nucleus).

“Based on demonstrated results, where the average increase in total nacre deposition was about 0.73mm in six months, BioPacific’s technology will increase total nacre deposition by 1.5mm in one year,” Ward says. “Such an increase at this desirable size can increase the value of that pearl by nearly a factor of three, resulting in significantly higher farm profits.” This means farmers could charge less, and so could retailers.

For akoya pearl farmers, the growth enhancer may be the only way to harvest pearls larger than 8mm, Ward says. “For Japanese saltwater and Chinese freshwater cultured pearls, [the enhancer] can allow farmers to produce huge all-nacre pearls without the need to bead nucleate.”

– Robert Weldon, G.G.

Copyright © 2001 by Bond Communications