Live Discussion: The New Bead-Nucleated Freshwater Pearls from China

[Yens]

I was actually on that same trip. Here's some info.

This mussel shell serves as a natural timeline of growth. Each red “X” marks an estimated age stage along the shell’s growth lines—from top to bottom:

• The first mark near the hinge shows a baby mussel about 1 month old.
• The second mark reflects around 1 year of growth.
• The third mark corresponds to roughly 2 years old.
• The fourth indicates 3 years.
• And the final mark at the bottom represents a mature mussel at approximately 4 years of age.

These growth rings are key to monitoring development and selecting ideal ages for grafting or harvest in pearl cultivation.

The image provides a detailed look at the internal anatomy of a mussel, highlighting key areas relevant to pearl cultivation:

• Stomach Area (Red Circle):
  This region contains the mussel’s stomach, essential for digestion but not directly involved in pearl formation.
• Gut Area (Green Circle):
  Marked in green, this is part of the digestive tract, responsible for processing nutrients.
• First Graft Area (White Circle):
  The white-circled area is where the first graft procedure takes place. During this step, a small piece of donor mantle tissue is implanted to initiate the formation of non-nucleated pearls or to prepare the mussel for future bead nucleation.
• Second Graft Area for Baby Edison Bead Nucleated Pearls (Blue Circle):
  The blue circle shows where a second graft is performed for producing baby Edison pearls. Here, a bead nucleus and a piece of donor mantle tissue are implanted to stimulate the formation of bead-nucleated pearls.
• Mantle Tissue for Nucleation (Outlined by Black Lines):
  The area outlined in black indicates the mantle tissue, which is harvested and used for nucleation. However, the tissue from this particular mussel is considered too old for optimal pearl production. Farmers prefer using mantle tissue from younger mussels, typically 7–10 months old, as it yields better results for both first and second grafts.

Also here's a quick video of how they do the nucleation.

 

[BWeaves]

Fascinating! Thank you, Yens.

Loved the video. I'm amazed that every time I've watched pearl cultivation, every person has a different way of doing it. I've seen the mantle tissue being put in, and then the bead. I've seen the bead put in and then the mantle tissue. And in your video, the mantle tissue and bead are put together, and then inserted at the same time.

 

[PearlyLibrarian]

I'm on page 436 of Pearls by Strack, in the section called "Growth Rate and Growth Time." This is for the sankaku mussel a.k.a. Hyriopsis cumingii.
It says the growth rate ranges from 1mm-5mm per year, depending on water temperatures and the season, with other factors listed as also influencing the rate.

"The growth rate appears to decrease with time...The size is reported to be 3 mm after one and a half years and 7mm after three years. One source quotes a period of four years for pearls of 9 mm and a time of six to seven years for sizes above 10 mm. Other sources claim eight to ten years for pearls above 9 mm and five to eight years for for pearls from 7 mm to 9 mm. Pearls below 7 mm are claimed to require about four years.... "

So you see the information is all over the place. But bottom line-- it takes time for pearls without a nucleus to grow large! Meanwhile the mussel needs to be fed and kept alive. Clearly time is saved by starting with a bead nucleus. And time = money.

Thanks for this research! Growth time plus the increased round shape consistency and improved color - yeah, I expect this will become the “new normal” purely from economic incentives to the farmers (and likely as the high tech setups that were shown become more prevalent. Perhaps really small farms will not have the tech to be able to do this OR the really small farms will cease to exist?)