[Caitlin]

http://www.jckonline.com/article/CA6330322.html

Pearl Expert Says CFWCPs Not Tissue Nucleated
By Gary Roskin, G.G., FGA -- JCK-Jewelers Circular Keystone, 5/1/2006
German pearl expert Elisabeth Strack, author of the book Perlen, says Chinese freshwater cultured pearls (CFWCPs) are not "nucleated" when mantle tissue is inserted into the oyster. "They are activated," says Strack. "The inserted mantle tissue is the precursor of the pearl sack in which the pearl grows." Strack, director of the Gemmological Institute of Hamburg, notes that this scientific fact has been known for several years.
Pearl dealer Marc Freeman has been promoting his PurePearl line of large, round CFWCPs as consisting of 100 percent nacre, and the American Gem Trade Association’s Gemological Testing Center laboratory has recently changed its reports to read that these pearls consist of "approximately 100 percent nacre."
But GTC still labels these pearls "tissue nucleated." However, most other laboratories identify them as "mantle- tissue nucleated," with no comment on nacre thickness.

[purepearls]

What's that about the PurePearl Line by Marc Freeman???? Trademark infringement!

[Kevin Canning]

I was waiting for you to jump in on that line Amanda - I hope you can take your trademark back from him.

[Caitlin]

Marc Freeman has a booth in the main Lobby of the Agta gem show and probably will be attending the lecture as well.

[jshepherd]

I am going to take that rare step here and disagree with Strack's assertions.
I do not think it is completely correct to call freshwater pearls tissue activated instead of nucleated. It is true that the tissue often grows into the pearl sac. But it is also true that the host can treat the tissue like an intrusion and produce a sac around the graft. It also may happen that the new tissue fuses with the host, and a pearl sac is created. This is why within even a single strand of pearls, some x-rays will show a hollow space, some show 100% nacre.
The mussel is nucleated. If we were to change the terminology to activated, this would be the same for all pearl producing mollusks. But since both Strack's and Freeman's assertions are not completely correct 100% of the time, the term "tissue activation" is incorrect.

[pierrettedE]

hmm, I'm leaning on Jeremy's side here. Wouldn't the terminology have to change in all cases where tissue is introduced into a mollusc to the eventual production of a pearl. As fond of FWPs it seems to be muddying a term (nucleation), and would further confuse the general public.

Pierrette