Featured Back of a brooch

It’s really lovely, red, green, blue, purple, orange. No hallmarks, not magnetic and I think likely to be silver but I’ve never seen one quite as colourful as this at the back. Must be a casting with heat and chemicals result? Charity shop buy. 2 and a half inches long, 1 inch wide. Edwardian perhaps? Any thoughts? Thanks for looking.

 

The rainbowing often means silver plate, but with jewelry and the odd finishes it's not definitive. Pretty pin. It's not as old as it wants to be; the clasp and hinge are new-ish.

 

I didn’t know about the rainbow indicating plate so thanks for that. I just found another example of the brooch on Etsy, listed as plate but no rainbow, really clean underneath and with a rollover clasp.

 

Your thoughts about the rainbow sheen reminded me of a post I made about it a long time ago now! I need to reread but there may be something of interest in it.
https://www.antiquers.com/threads/rainbow-tarnish.35546/

 

Missed that I think as I didn’t post a ‘like’ anywhere.
It is interesting especially concerning the coins. I actually prefer the back of my brooch to the front.

 

Aww the conservation link is dead.

 

Same for me. Interesting!