The Science of Nacre Deposition

[CortezPearls]

I found these two articles, each referencing the same scientific study, that basically explain the why some pearls are symmetrical (of course, they are focusing on symmetry and not on its opposite) and it is quite interesting!

Article 1: New study shows how pearls grow into their symmetry - Materials Today
Article 2: How an oyster builds a perfectly round pearl | Science News

And I especially enjoyed this comment:

"We humans, with all our access to technology, can't make something with a nanoscale architecture as intricate as a pearl," said Robert Hovden, assistant professor of materials science and engineering at the University of Michigan and author of a paper on this work in the Proceedings of the National Academy of Sciences. "So we can learn a lot by studying how pearls go from disordered nothingness to this remarkably symmetrical structure."

The original article can be read here: How pearls achieve nanoscale precision | University of Michigan News (umich.edu)

 

[jshepherd]

Here is the source - https://www.pnas.org/content/118/42/e2107477118

The Science News article took the research in an entirely different - wrong - direction. The author used the grain of sand myth, extrapolated information from the article and came up with a premise that is completely incorrect. She is assuming natural pearls are round (instead of 99.99% baroque and non-round) and accepting the myth that the form around sand or other debris.

 

[CortezPearls]

Indeed jshepherd they saw things from the perfect sphere point of view (and they were working with keshi, or so they say...which are rarely -if ever- round). But the interesting bits have to do with the nacre thickness deposition and the way each layer interacts with each other through what they say is the "1/f noise":

The spectral density of a pearl’s tablet thicknesses follows power-law decay across low to mid frequencies, colloquially called 1/f noise, suggesting nacre growth has correlations that extend over a wide range of time scales with cooperative effects linked to environmental changes.

Just this quote gives me an idea of an active force or intelligence working on nacre deposition. And this is very interesting.
And for the most part...there is a lot of physics, and not really in my area of expertise, so I can't really grasp most of the information presented on the main -scientific- article. Still, interesting ideas floating around there.