Vintage Art Deco Geometric Poured Glass Cabochon & Stone Brooch

This gorgeous unmarked piece has been difficult to determine era & material. Google imaging repeatedly attributes French designers however, nothing confirmed. Quality made piece features an angular shape with matte gilt gold plating over a thick brass base, raised Egyptian style engravings/lines with simulated “stones” imitating lapis lazuli & malachite with a central purple colored poured glass cabochon. Light plating loss on the back center & there is a copper like color that is visible on the metal around the stones - not sure what this is but it adds even more uniqueness. Hallmarks: None Measurements: 3” wide x 1 1/2” length Condition: Beautiful vintage condition with notes