Art Deco marquise-cut sapphire ring

This piece is a decorative cocktail ring featuring a prominent marquise-shaped (navette) orientation. At the center is an elongated, faceted blue gemstone, likely a synthetic sapphire or spinel, which is common for jewelry of this period. The stone is set within a white metal mounting, historically consistent with either platinum-topped gold, white gold, or sterling silver, displaying characteristic aged patina and oxidation in the recessed areas. The surrounding metalwork exhibits detailed milgrain edging and intricate hand-carved geometric and foliate motifs along the elongated shoulders, showcasing craftsmanship typical of the Art Deco or Edwardian eras. There are no maker's marks or hallmarks visible in this close-up view, meaning the identification of its age and style rests entirely upon the visual characteristics of the navette silhouette, the bezel construction, and the decorative hand-engraving. Condition-wise, the ring shows expected surface wear and patina consistent with age, but remains unauthenticated regarding its exact metal purity or gemological composition.

Based on what I can see in the photograph, this piece is an Art Deco-style navette or marquise cocktail ring featuring an elongated, faceted blue gemstone set in a white metal mount with detailed milgrain and hand-engraved motifs. The styling strongly suggests production from the 1920s to 1930s. However, I cannot verify from a photo the metal purity or the exact gemological identity of the central stone; synthetic sapphires and spinels were extremely common in this period, though glass or natural corundum remain possibilities. A physical inspection including gemological testing and an acid or XRF metal assay would be needed to establish the exact materials. My value estimate of $350 to $600 assumes the hypothesis that this is a period Art Deco piece crafted in white gold or platinum-topped silver/gold with a period-appropriate synthetic sapphire, exhibiting typical age wear. Demand for genuine Art Deco jewelry remains consistently strong in the antique and vintage market. If in-person examination reveals the piece to be crafted from sterling silver with paste/glass, or if it represents a later vintage reproduction 'in the style of' the 1920s, the market value would likely soften to the $75 to $150 range. Conversely, should the mount test as platinum with a natural unheated sapphire—an unlikely but not impossible scenario—the valuation would increase significantly. Hallmark inspection, advanced gem testing, and hands-on appraisal are necessary to validate these working assumptions.