Vintage Silver Filigree Brooch with Turquoise Accent

This exquisite brooch features intricate silver filigree work, beautifully complemented by a striking turquoise, The stone in middle is not polished, has a gritty feel to it and cool to touch It is signed but I cannot read the label. It was almost black but i used a silver cloth and paste to bring the silver back Has unusual pin pivot Measures about 1.75 inches round Dates to 1920’s to 1940’s early Egyptian Revival Era. The clasp is iof vintage origin consistent from this era