Interesting. I’d assumed that this was due to pollutants in the air,
and the interaction of dust caking onto surfaces that are subjected to
cycles of mist and drying (rather like my bathroom’s chrome surfaces).
I can quite imagine that pearls could get such a coating, from
the outgassing of the plastic container.
Catrina Warner mentioned that it had only been six months since she’d
bought the pearls. I find it hard to believe it would happen in six
months, unless her pearls are being subjected to more temperature
change than I would consider normal. I know of a strand of Tahitian
pearls that has been sealed in a plastic bag for 2 years (with regular
exposure to room air and sunlight, and the occasional washing), and it
hasn’t become blotchy.
Catrina, could you followup for us and let us know some more about
your pearls? Are they freshwater? Akoya? Dyed?