MSC
Natural Pearl Lover
- Joined
- Oct 11, 2012
- Messages
- 2,861
In my experience, these tend to be surface marks on the pearl and not a stain. As pearls live in the ocean with a pH of 8.2 slightly basic, the most damaging solutions to the nacre are acidic solutions (just like teeth). A slightly basic solution of baking soda or washing soda shouldn't harm the nacre. I will have to get out my chemistry set! We have all seen the harmful effects on nacre from acidic chemicals!
Pearls reside in tissue though and aren't in contact with salt or freshwater while in situ... Dave would know what the pH of various bivalve tissues are, generally, I would think.