Vintage retailer rare gemstone gold brooch

Product Name: Vintage retailer rare gemstone gold brooch
Absolutely beautiful brooch. It's not magnetic at all retailer I can't find any type of marking with my loop. Unsure of age. Seller thought the diamond looking stones may or may not be real. So on this one I'm unsure. I'm thinking this one is filled or heavily plated. I think that is a fire type opal bc of all the pink and purple in it. I'm unsure what type of gemstones this can be worn as a pendent on the necklaces through the pin part. It could easily be worn or attached to multi strand necklaces or chains. As long as it's small enough to not bend that pin on brooch. This is not too big or too small it's perfect. Beautiful . Used very good condition. So the opal is genuine in center all stones are prong set prob worth a lot more then what I'm selling it for.The diamond like stones surround it there is a zoomed picture on last two of 2 of those n The opal. not showing it well in pictures.Seller didn't know if real or not of the diamond accents or gold. Very old. Pic does no justice! Untested.