It is Art Nouveau in style. The watch runs but I have not times it so it may need service.The case is not clearly marked as to content but it tests a little purer than 18kt solid gold. There are a few small hallmarks but I cannot make them out. This probably an 11/0 size or 9 3/8 lignes and it is probably Swiss made. The case has enamel, seed pearls, and some clear stones that I suspect are rough cut diamonds. They just have few facets compared to a single cut or a brilliant cut diamond. The enamel has some damage and 1 seed pearl is missing. The diameter without the crown part is about 25.4mm. The lids close securely and the hinges are nice and not loose. The watch pin sets smoothly. The total weigh is about 17.1 grams. The item "Antique Pendant Ladies Pocket Watch Solid 18k Gold Enamel C. 1900" is in sale since Wednesday, February 5, 2020. This item is in the category "Jewelry & Watches\Watches, Parts & Accessories\Pocket Watches\Antique". The seller is "fourthstreetgoodies" and is located in Huntingburg, Indiana. This item can be shipped worldwide.