Thank you for contacting Mearto with your appraisal inquiry.

It is a beautiful pendant. Such vintage jewellery are being offered at auction on a regular basis.
It is a lovely pendant in a beautiful design - very classy and elegant. It is made of sterlingsilver - that is 925 mark - this mark was introduced in the early 1900s - and style wise the ornamentation is from the first half of the 1900s, so now it has been narrowed down to having been made around 1920-1940. As for the makers mark AF it is next to impossible to figure out who is the maker. The design could be both european and american. Many of the decorative elements were popular in both areas of the world at the time, and without any provenance or more marks it is very hard to come closer to a country of origin let alone the maker. However this is often the case with vintage jewellery that it is really hard to determine when you lack information. The opal is amazing and has a fantastic shine and glow.

I believe that the pendant would attract the attention of both collectors and dealers if it came up for auction.
The estimate provided is for a well-advertised specialised online jewellery auction, where I believe the pendant has the best chance of realising its fullest potential. However, there is no measurement for the sentimental value you might attach to the pendant. Retail "asking prices" can be higher and vary.

Please let me know if you have any additional questions. I’m happy to help.
Thank you