Art Deco onyx and diamond ring

This piece is a vintage ring featuring a central oval-shaped black onyx stone mounted in a white metal setting, which appears consistent with white gold or platinum typical of the Art Deco period. Set directly into the center of the onyx is a small, round, single-cut or old-mine-cut diamond secured within a raised hexagonal or geometric bezel, a characteristic decorative motif of early 20th-century jewelry design. The bezel surrounding the main onyx stone exhibits fine milgrain detailing along its outer edge, enhancing its antique aesthetic. The shoulders of the band show faint decorative etching or engraving, though finer details are partially obscured due to lighting and wear. The overall physical condition displays moderate surface wear and expected patina on the metal surfaces, consistent with age and frequent use, but no major structural damage or missing elements are immediately apparent from the visual evidence provided. There are no clearly legible maker's marks or hallmarks visible in this photographic angle. The identification of this item as an Art Deco style ring is based entirely on the characteristic geometric configuration, milgrain work, and stone combination visible in the image, and remains unauthenticated.

Based on what I can see in the provided photograph, this vintage ring displays characteristics consistent with an Art Deco design, including a central black onyx stone, a raised geometric bezel, fine milgrain detailing, and a single-cut or old-mine-cut diamond. I cannot verify the metal purity, stone quality, or internal integrity from a photo alone, as a physical inspection and gemological testing would be needed to confirm these elements. The estimated value range of $1,200 to $1,800 is given for an item of this type assuming the stylistic attribution to the Art Deco period is correct. Market demand for antique and period-style geometric jewelry remains relatively steady among collectors of vintage accessories. However, because no clearly legible maker's marks or hallmarks are visible, this valuation is conditional. To fully verify the age, materials, and potential authorship, an in-person examination by a qualified gemologist, hallmark verification, and possible scientific testing of the metals and stones would be necessary. If physical inspection reveals that the item is a later reproduction, replica, copy, or made simply in the style of the Art Deco period rather than being a period-authentic piece, the value would decrease significantly, typically falling into the $300 to $600 range based purely on the intrinsic value of the metal and small diamond.