Help me confirm the origin of these pearls

[jc12345]

Hi,

My mother gave these pearls to my wife when we left to stay in another country. She said I should insure them. Before I do that and go theough the effort to have them appraised for insurance, I would like to confirm the origin. She said she purchased them from a Mikimoto store in Japan in 1970 when she and my father was there.

I dont know if it is the orginal box and I dont have any paperwork. They are gritty to the teeth and 8mm in size.