Thanks for reaching out! What a lovely and interesting bracelet design featuring gold and Biwa pearls!
Now, there is only so much I can tell from a photo but I would guess these are Japanese Biwa pearls. Biwa pearls are named for Lake Biwa in Japan where the first attempts were made at culturing freshwater pearls. The Japanese were already producing gem quality saltwater cultured pearls in the ocean and saw the value of culturing pearls in fresh water. Freshwater lakes are more accessible and the cost of a cultured pearl farm on a lake is more affordable than having an operation in the ocean. Plus, the risk of death by widespread disease, bacteria or weather patterns is lower once you come inland!
These first freshwater pearls had amazing luster but were shaped like rice krispies. Pearl farmers had a tough time creating round pearls. By WWII most attempts on Lake Biwa were abandoned and the Chinese took over freshwater pearl cultivation. China now produces over 98% of the world's freshwater pearls. Some pearls shaped like these can still be found from freshwater pearl farms in China. Pearl sellers still call them "Biwa pearls" although they are, of course, not from Lake Biwa.
I hope that helps! It is lovely bracelet. I hope you can find someone who will treasure this piece as I am sure your Mom did.
All the best,