Vintage Black Marcasite Oval Brooch Women Accessories. Silver W/PUSH -PULL CLASP

vintage Art Deco marcasite and black onyx openwork brooch, valued for its geometric symmetry and intricate open-back construction.   Key Characteristics & Material Breakdown  Design Era: The combination of strong geometric framing, symmetry, and architectural shapes dates this piece back to the Art Deco period (typically the 1920s to 1930s) or a later mid-century revival.  Central Inlay: The central square setting holds a black onyx cabochon or faceted glass inlay, which acts as the focal anchor.  Metal & Setting: The brooch body is likely made of 925 sterling silver I believe but it is NOT marked sterling or could be  a silver-toned pot metal. The dark, aged background (patina) is deliberately used to make the settings pop.  This broch has a Trombone clasp as so called push and pull, for safety. This type of clasp was introduced in Europe in the early 20th century. Good used condition and quality.