Fijian Natural Pearls History?

I grew up in Fiji. My father Donald McLoughlin O.B.E was the Solicitor General of Fiji and oversaw the writing of their Constitution upon independence. He gave me a pearl necklace on my 16th birthday. He told me that they were Fiji pearls collected over the years since I was born, to be a perfect match.

I don't have the box that they came in because they disappeared a year later. 5 years later they arrived in bubble wrap by mail. Apparently the man I was living with at the time they were lost had 'found' them and out of guilt decided eventually to give them back. I bought an empty box at a flea market and kept them in it.

I had the pearls valued in Western Australia and was told that they were Mikimoto pearls because of the box. How can I find out what sort of pearls they really are?