Monet heart charm chain-link choker

I have a vintage gold-colored heart charm chain-link choker necklace made by Monet. I would like to know what era or year it might be from?

The whole necklace is approximately 15.5" long. It seems to be made out of brass or some gold plate. The left part of the pictured clasp says, "MONET" in all caps with NO "TM" or copyright symbol. The heart charm is hollow, not three-dimensional, but "cupped." Bought it at a Value World in Detroit. ;) My guess is '60s or '70s; wear seems vintage but in good condition.

Thanks!