Years ago when I was on my first cruise we pulled into the Maldives, an archipelago in the Indian Ocean.
I was always looking for gifts for my Mom and assorted loved ones. What caught my eye were black pearls:
Exotic Places: Black Pearl Jewelry souvenir From bora bora island That is the only link I could find.
I bought some for my Mom and Sisters and they were a huge hit. Granted, they all had white pearls so this was, at least to us, unique.
Good luck and congratulations, Hugh and the Mrs.!