A rivière is a river: stones graded from largest at the front to smallest at the back so the necklace appears to flow rather than to repeat.
The clasp is the part nobody photographs and everybody uses. Ours is a box clasp with a figure-of-eight safety, openable with one hand, and it is rated at four times the weight of the necklace.
Hélène D. (verified owner) –
The clasp is the thing I would tell people about. One hand, no mirror, no help.