I finally finished my Mexican agate/bead necklace yesterday.
I decided to put the big clasp on, at least temporarily because in all the time since I bought the beads last year, I have not been able to find another that I liked.
I still feel this isn't the final clasp but it will do until I find the right one.
The beads are threaded onto a very fine silver chain. The spacers are African clay beads (black and white) and antique black glass beads.
I wound up making the jump rings out of pieces of regular dress pins. Anything larger in diameter wouldn't fit into the fine links of the chain.
It works well, actually, since I have this nifty pliers tool for making links.