I honestly didn’t realize what I was getting myself into here. I thought it would be seasonally appropriate to post some vintage jewelry ads. I was little prepared for how vast a universe that is. Ads are a chief tool for identification and dating. Vintage jewelry is so widely collected that the online resources are plentiful. As for the Trifari pieces in the ads here, if there's something you just have to have, you might be in luck.
Morning Glory Antiques has a number of pages for Trifari jewelry, where they pair an actual piece with the its original vintage ad.
Trifari, late 1930s to mid 1940s
Trifari, mid-1960s Trifari, c. 1950 Coro, c. 1958 Castlecliff, c. 1946 Richelieu, c. 1958 Monet, c. 1966Monet, c. 1963 For about a decade, starting around 1950, Cadillac
ran ads pairing cars with bling from luxury jewelers,
Van Cleef & Arpels, Harry Winston, and Cartier.De Mario, c. 1958