Dear Dianne,
from our many many years of experience, there are no such pearls either cultured or naturally grown from Halmahera Islands, even if they would, not in such an high amount ( you said 3kg? ). However, the golden and champagne could be Keshi Pearls, Maluku is know for good quality Keshis also in round and drop shapes, however they would have been cultured.
The pinkish ones are pretty sure freshwater pearls.
Local Fisherman usually get plastic bags full of freshwater pearls from the farms and try to sell them as natural self harvested pearls.
If you want to make sure, send on of the pearls to GIA to get them tested.
Good Luck!
Sven