Vintage Mid-Century Marbled Green Lucite or Celluloid Brooch

This item is a vintage costume jewelry brooch featuring a distinctive Mid-Century Modern geometric aesthetic. The piece is constructed from two triangular segments of marbled green plastic, likely Lucite or Celluloid, set within a gold-toned metal frame. The green material exhibits a pearlescent, 'end-of-day' swirled pattern with varying shades of lime and seafoam green, imitating the look of natural jade or malachite. The metal framework appears to be gold-plated brass or a similar alloy, showing a thin, elegant bezel that emphasizes the sharp angularity of the design. The item is medium-sized, approximately 1.5 to 2 inches in length. In terms of condition, there is visible surface wear including fine scratches on the plastic inserts and noticeable tarnishing or loss of plating on the metallic edges. The pin stem is visible at the back, appearing straight though it shows signs of age-related patina. No maker's marks are visible in the provided view, but the style is consistent with 1940s-1960s costume jewelry manufacturing. The craftsmanship reflects mass-produced quality typical of mid-20th-century fashion accessories, valued for its bold color and architectural silhouette.