This necklace was a pain in the ass to make. I used these large sterling silver rings, but didn't use large enough sterling wire. The rings were hard to work with (complicated by mean bending them into ovals) and the damned thing kept coming apart. But a little solder helped quite a bit.
The unique ring shape and the fish beads (glass and turquoise stone) ended up pretty cute, though - and made an appropriate present for a biological oceanographer.