Is it really Kojima? What are these pearls?

[MintyFresh]

I purchased this brooch from EBay for $75. Seller listed it as Kojima but there’s no receipt or identifying marks. However, it was so pretty, I took a chance. Does anyone know what kind of pearls these might be? The brooch measures about 2 inches wide. Perhaps the seller is even a member?

One of the long outer pearls is just a bit loose. Can I glue it myself or should I take it to a jeweler?