I've owned this one for decades. It had no tarnish when I found it and it's never tarnished a bit since. It is an 18th century vest 'necessaire' larger than most, and fitted with old silk velvet inside, but no longer has contents. Wider than most of the vest necessaire I have collected, it is by the same maker as the one on display in the Louvre collections (see my photo added), which is also this same slightly larger size. Did it once have a fitted scent flacon, flask, bottle? I suspect it did. All I have is the etui, the case. Photos show it well. Again, it is not solid 18k gold, but a 'vermeil' on a base metal. I can't see silver marks, and I can't be sure if it's silver or brass (not peeling the old velvet, sorry). Full measurements are noted on the photos.
Very good to excellent condition, no dents, a thick gauge 18k plate which has not worn through at any places (you'd see some tarnish if silver or brass beneath it if it were thin enough to have worn off in polishing or use).
