Thank you for contacting Mearto with your appraisal inquiry.

It is a beautiful rose brooch/pin. Such vintage jewellery are being offered at auction on a regular basis.
I would say that the rose brooch dates from the first half of the 1900s. Around the 1940s flowers were very popular in jewellery and due to the 2 world war gold- and silversmiths looked towards using other materials than silver and gold due to wartime restrictions.
As for the other material I tend to believe that it is bone or some sort of compressed ivory look a like material. The colour is almost too white, however this is very hard to determine from photos alone. In order to determine if it is ivory, bone or another material you would have to examine it in real life. The metal appears to be silverplated.

It is a nice piece of jewellery that would attract the attention of both dealers and collectors if it came up for auction.
The estimate provided is for a well-advertised specialised online jewellery auction, where I believe the rose brooch has the best chance of realising its fullest potential. However, there is no measurement for the sentimental value you might attach to the brooch. 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