Costume cocktail ring appearing to be sterling silver with opal and sapphire-style stones

This item is a decorative cocktail ring featuring a prominent oval-cut cabochon center stone that is stylistically consistent with a white opal, displaying characteristic play-of-color with green and pink flashes. Surrounding the center stone are several small, dark blue round-cut stones consistent with the appearance of sapphires or blue glass. The stones are secured in a multi-prong setting on a split-shoulder band. The metal exhibits a bright luster with some dark oxidation in the recessed areas of the setting, which is often seen in sterling silver or silver-plated jewelry. The owner reports that the interior of the band is stamped '925', which is a hallmark typically indicating sterling silver (92.5% purity). However, this mark is not visible in the provided image and remains unverified. The overall construction is in a retro or late 20th-century style. Without physical testing of the stones or metal, their identity cannot be stated as fact, as synthetic alternatives frequently mimic these aesthetics. Visible condition appears good with minor surface scratches and expected patina on the metal surfaces.

Based on my visual analysis of the provided image, this cocktail ring appears to be in a style consistent with late 20th-century costume or bridge jewelry. The central cabochon exhibits a play-of-color suggestive of a white opal, while the surrounding blue stones are stylistically similar to sapphires or colored glass. Per user submission, the band is reported to bear a '925' mark. While I can see surface patina and luster consistent with sterling silver, I cannot verify the metal's purity or the stones' mineral identity from a photograph alone. These materials could easily be synthetic or silver-plated base metal. My valuation assumes the hypothesis that the ring is indeed sterling silver with a genuine (likely lab-created or lower-grade natural) opal and glass or synthetic sapphire accents. In the current secondary market, decorative silver rings of this type typically sell within the $45 to $85 range. This estimate is heavily dependent on the unverified '925' hallmark. If physical testing were to reveal the metal is a base-protein alloy or the stones are plastic, the value would likely drop below $15. Conversely, if the stones were identified as high-quality natural Australian opal and earth-mined sapphires, the value could exceed this range. To establish a more certain value, I recommend an in-person examination by a GIA-certified gemologist to perform a scratch test, thermal conductivity testing, and microscopic inspection of the stone inclusions. Verification of the hallmark under magnification would also be required to support the sterling silver attribution.