Antique Victorian 10 Carat Rose Gold Onyx Monogram ‘D’ Signet Ring – Patented By William Leidig, 1890

A remarkable example of late Victorian ingenuity and craftsmanship, this exceptional antique signet ring was crafted in the United States and features the innovative ‘Princess’ interchangeable initial system, patented by William Leidig of Newark, New Jersey, on 26 August 1890 (U.S. Patent No. 435,068). Beautifully crafted in warm 10 carat rose gold, the ring showcases a polished rectangular plaque of black Onyx measuring 17.4 x 12.3mm, surmounted by an elegant openwork old English initial ‘D’ in gold. Unlike traditional signet rings where the monogram is engraved directly into the stone, this ingenious Victorian design features the initial mounted onto a finely engineered gold plaque, preserving the polished onyx beneath while creating wonderful depth and dimension. One of the most fascinating aspects of this ring lies hidden within its construction. The decorative initial is secured by an ingenious pivoting locking screw mechanism concealed beneath the ring. Patented by William Leidig, the miniature screw pivots into position before tightening into the setting, firmly securing both the onyx and monogram in place. This clever mechanical system allowed the initial to be removed and replaced with another, enabling the ring to be personalised without altering or re-engraving the stone itself—a remarkable innovation for the Victorian era and a wonderful example of 19th-century jewellery engineering. The shoulders are beautifully decorated with finely engraved scrollwork that complements the elegant proportions of the ring, while the polished rose gold band provides a comfortable fit and timeless appeal. More than 130 years after its patent was granted, this is not only a beautiful antique signet ring but also a rare piece of jewellery history that perfectly showcases the Victorian fascination with innovation, craftsmanship and mechanical design. A beautifully solid ring weighing 5.99 grams, it sits low rise to the finger, measuring 4.25mm, while maintaining an impressive presence on the finger. The ring remains clearly stamped ‘Princess’ together with ‘PAT-AUG-26-90’, commemorating the original patent date and confirming its connection to this celebrated Victorian invention. Stones x1 Polished black Onyx Measurements 1.74 cm x 1.23mm Rise- 4.25 mm Weight 5.99 grams Marks XRF tested for 10ct Hallmarked with; ‘Princess’ PAT-AUG-26-90 (William Leidig of Newark, New Jersey, on 26 August 1890) Fingers Size P or 17.99mm diameter or US7 3/4. Can be resized up 2-3 down 2 with any competent jeweller. Condition Very good to excellent vintage condition. No chips or damage to Onyx plaque; applied ‘D’ monogram sits flat and secures perfectly due to the mechanical ‘screw’ back to the verso. The gold is lovely, very solid and substantial, with no thinning or loss to detail. The shank is very strong, thick and only shows subtle irregularity to the shape under very close observation, only noted for accuracy and minor superficial marks to rear of shank, a jeweller could polish this as desired. Stamps inside shank are clear and legible. Wonderful, rare to find ring! Explore Our Collection Discover our curated collection, each piece with its own distinctive character and exceptional craftsmanship. View The Collection