An exceptional antique opal and diamond brooch crafted in platinum and 18K yellow gold, centered with a large rectangular opal weighing approximately 52.07 carats. The opal displays beautiful flashes of green, blue, yellow, and orange play-of-color across a soft milky body, giving the piece a dreamy and luminous presence.

The opal is set within an ornate platinum filigree frame, decorated with delicate pierced scrollwork, floral motifs, and fine milgrain detailing. The frame is accented with 192 rose-cut diamonds totaling approximately 1.00 carat, adding subtle antique sparkle throughout the design without overpowering the opal.

The back is finished in 18K yellow gold, with a traditional brooch pin fitting. The combination of platinum front work and yellow gold reverse is very typical of fine early 20th-century jewelry construction.

A romantic and highly detailed antique brooch, beautifully balancing a dramatic opal centerpiece with intricate diamond-set filigree work.