Modernist Gemstone and Mixed-Metal Statement Ring

This item is a contemporary or mid-mod style statement ring featuring a prominent cabochon gemstone as its centerpiece. Based on the deep, opaque coloration and smooth surface, the stone appears to be black onyx, hematite, or perhaps a dark star sapphire, polished into a high-dome oval shape. The stone is set into a substantial, wide-profile square mount that displays two distinct metallic tones, suggesting it is crafted from a combination of materials such as copper and brass, or possibly rose gold and sterling silver. The face of the ring measures approximately 20mm by 20mm. The construction shows a flattened, geometric face that contrasts sharply with the organic, rounded form of the central cabochon. While the image is low-resolution, there appear to be visible signs of surface oxidation and a light patina developing on the metal surfaces, particularly near the edges of the setting. Significant wear is not immediately evident, but the dulling of the metal suggests it has been handled and may require professional cleaning to restore its original luster. No visible hallmarks or maker's marks are discernible from this angle, but the robust build quality and symmetrical proportions indicate a certain level of artisan craft characteristic of mid-to-late 20th-century studio jewelry or modern boutique designs.