I agree with pearlescene. The two round yellowish strands appear to be imitation (with a very pretty clasp). The pearl shapes on the station necklace are lovely.
If you knot them on a two strand clasp, just twist to the desired twistiness, then fasten the clasp. They will stay twisted till unclasped. Adding a third strand into the mix might be a good idea as the more twists, the shorter the necklace becomes.