Non nacreous pearls are plentiful. Only those with SPECTACULAR traits are easy to sell, even at really high prices.
I can always ask...but let me show you some natural clam pearls I have...
The larger one measures 12 mm. I have been offered less than $100 USD for all of these.
But here I have some nice Conch Pearls...worth thousands of dollars (as a lot).
Maybe somebody that collects pearls just for a biological collection will want the pearl. But I don't know how easy it will be to find him/her.