Renne, I've been told lots of things too about pearls that turned out not to be the whole truth. This was the reason I decided to create a website devoted to informing the general public about Antique Jewelry and Pearls.
I am not convinced these pearls are Mikimoto pearls. They may even be pearl imitations. The build-up around the drill-hole of the pearl at 12 o'clock (second last image) makes me suspicious.
What is the Mikimoto trademark? How do I know that my pearl jewelry is Mikimoto?
You can always identify Mikimoto jewelry by their trademark, which is either the outline of an oyster or the Mikimoto name engraved on every jewel. This engraved mark can be found in the following locations:
1. Necklaces and bracelets: back of clasp. Nowadays they are also fitted with a signature M charm. As the clasp is the only place in a strand or bracelet where the Mikimoto trademark is engraved, it is not possible to appraise a strand or a bracelet as genuine Mikimoto without it.
2. Earrings: on post, earring nuts or back of earrings
3. Rings: inside the shank
4. Pendants: on the back of the bail
5. Brooches: on the underside of the brooch
This information can easily be found at the Mikimoto America Website. http://www.mikimotoamerica.com/customer-service/assistance-and-contact