Mikimoto with a serial number on the clasp?

I recently got these pearls at an estate sale - they came in the case which was in the box pictured. I have never seen a Mikimoto necklace with a serial number actually on the clasp (nor am I familiar with a clasp that has a diamond rather than a pearl). The biggest pearl in the center is a 9mm and the smallest is a 7.5mm. Can anyone tell me if these are authentic, or anything about them?

The diamond clasp is used with their higher-grade necklaces, so maybe that's the reason for the serial number?
Why don't you call Mikimoto and ask?

Pearl Dreams said:

The diamond clasp is used with their higher-grade necklaces, so maybe that's the reason for the serial number?
Why don't you call Mikimoto and ask?

Click to expand...

I did call Mikimoto and they want $400 to assess. After a bit more research, I think these might be the limited edition of Marilyn Monroe pearls, released in 1999. Will continue looking…

I did immediately think of Marilyn Monroe's pearls in their box but didn't realize there had been a limited edition release. That must be it, then.

See this page:

Marilyn Monroe’s Mikimoto pearls (KAZUHIRO NOGI/AFP via Getty Images)

The jewellery from Joe Di Maggio​

The Mikimoto pearls, a 16 inch strand of 39 lustrous Akoya cultured pearls with a diamond clasp – amongst the most expensive pieces she owned – were a gift from Joe Di Maggio on their honeymoon in Japan in 1954. Monroe wore them throughout her life as a reminder of ‘happier times’. Later they passed through the Strasberg family before being sold back to Mikimoto in their original oval shaped, velvet box at auction in 1998. One of the only other fine jewellery pieces in Monroe’s collections, after her death, was the platinum eternity wedding band (again from Joe di Maggio) set with 35 baguette cut diamonds. As well as a petite vintage Blancpain (circa 30’s) watch auctioned off in 2016.

May I just add-- great find on your part!

Wow, that's an exciting coup! I didn't see anyone mention, 750 = 18K.
I couldn't find anything about how many necklaces were part of the limited edition, but it appears that the serial numbers increment.