Bought this chain today Kolmar & Jourdan mark + DOUBLE There are still a few specks of shiny gold, but most if it has a patinaed copper color. Is it possible to tell by the style when this was made? 1920s like some of the other K&J chains that can be found online?
Art Deco German Kollmar & Jourdan Double KJ Pocket Watch Chain Engraved c.1920 ...https://www.ebay.com/itm/356339661499
Nice links. Kollmar & Jourdan is a well known name in antique and vintage German jewellery. They were one of the major firms in Pforzheim, the German jewellery making town. Yes, it is doublé, a term for gold plating on base metal we also use, although we mostly use it for older pieces. I have written several posts about Amerikaner Doublé, one of the grades of plating in the German speaking world. Like Amerikaner Doublé, Doublé is also doublé.