French Rope Chain, 70s

A long chain from France, made in the 1970s. Solid silver, each link twisted like a small rope. Closed with a spring ring clasp, small enough to sit almost invisible against the chain. The length can be adjusted smaller by removing links, and if enough are removed, it is long enough to become a bracelet instead. There is a total of 25 links. Purity marks visible but illegible. 

Style it wrapped twice around the neck for more volume, or worn long as it is.