Vintage Rhinestone retailer Unmarked Brooch

Beautiful large vintage unmarked brooch. Fine workmanship with soldered rattail over the top of the completed brooch. It appears to be gold washed. The raw retailer edges from the rattail have been washed in gold.
Navette hématite, rhinestones and a fabulous center stone that reflects like an opal, depending on the light.
The fastener has a dent in it close to the hinge. Unclear if that was intentional to support the weight of the brooch or otherwise.
Measures 2 3/4 x 2 1/8"