This is a pretty gigantic Tahitian Pearl at 18.5 X 15.7mm. It is decorated with 1.8mm Diamonds. I have made this into one of my patent pending Pearl Gemstone Clasps. Send me your pearl necklace that needs a little updating, and I will set the rest of the internal clasp into one of the end pearls and then restring your necklace. You will have a wonderful new and contemporary piece. Grandmother would be happy that you are wearing it.
The second photo is of some 8.5mm Akoya pearls next to the clasp to give you an idea of how this might look in your necklace. Sorry the Akoya pearls are not included.