tahitian pearl with flaw

I bought a tahitian pearl pendant that has a large bale with diamonds and is 18k for $150.The total weight of the piece was 6 gms. The pearl has a beautiful nacre. However it has a flaw at the bottom that looks like the pearl has broken off completely at the bottom and been glued together. The bottom part is also a different color - greyish while the rest has greenish bluish beautiful hues. The flaw or division is not noticeable at all when worn and I did not notice it until after I had given the seller positive feedback on ebay.

The seller says it is natural, but sold it at a lesser price because of the flaw. Is it possible to have such a flaw? Second can I use the bale/bail on another pearl?

I tried uploading the pics but was told they were too large. Please let me know if I can send them to you another way.

Thanks!