Vintage Silver-Tone Geometric Openwork Pendant Necklace

This item is a vintage-style pendant necklace featuring a square, diamond-oriented geometric pendant suspended from a textured chain. The pendant is constructed from a silver-toned metal, likely pewter or a plated base metal, and features a complex openwork design with a central raised square element and radial cutouts. The centerpiece appears to be set with a pale, possibly translucent cabochon or glass inset, though the reverse view shows heavy oxidation and build-up. The metal surface exhibits a dark, heavy patina and significant surface wear, suggesting mid-to-late 20th-century production, possibly 1960s or 1970s Brutalist or Modernist influence. The back of the pendant reveals a rough texture and possible remnants of a maker's mark or stamp on the left-hand bar, though it is obscured by corrosion. The chain is an interlocking cable style with visible darkening. Condition is fair to poor, with noticeable grime, oxidation, and scratches throughout the metal surfaces. The craftsmanship indicates a mass-produced costume jewelry piece rather than fine jewelry, though the geometric architectural design is characteristic of mid-century costume accessories.