A Large Rock Crystal Pendant Depicting the Triumph of Neptune. Italian (crystal), English or Continental mount, 19th century. A magnificent and richly ornamented pendant, comprising a large oval plaque of finely carved rock crystal mounted within an elaborate openwork frame. The carving presents a dramatic mythological scene of The Triumph of Neptune, with the Roman sea god depicted holding a trident and standing authoritatively upon rocky terrain. He confronts a youthful sea deity—possibly a Triton—riding a hippocamp as waves crest beneath him. The scene, animated with movement and classical symbolism, reflects the enduring popularity of Greco-Roman marine iconography throughout the Renaissance and into the 19th century. The frame is adorned with white enamelled scrolls, interspersed with sapphires and old-cut diamonds in closed settings. Two mount variants survive: one in blue and white enamel with a diamond-accented border, the reverse in chased and pierced gold with a more restrained decorative scheme. The rock crystal plaque is likely of Italian origin, 19th century or earlier, and the mount—possibly English—is a fine example of neoclassical or historicist revival jewellery, likely produced in the mid-to-late 19th century as a cabinet jewel rather than a wearable pendant. An exceptional tour de force of lapidary carving and goldsmith’s art, this pendant was conceived less for wear than for display, likely within a connoisseur’s treasury or Kunstkammer.