Vintage 18K Gold Plated Black Onyx and Rhinestone Cocktail Ring

This is a vintage ladies' cocktail ring featuring a large, oval-cut black onyx cabochon as the central focal point. The ring is constructed with an 18K gold-plated base metal, showcasing a distinct S-curve or 'swirl' decorative element that crosses over the face of the stone. This decorative gold-tone wave is accented with three small, round-cut clear stones, likely rhinestones or cubic zirconia, set in a diagonal row within a textured channel. The onyx stone is secured by four visible prongs. The band is a simple, slender round shank. On the interior of the band, a partial hallmark is visible, which appears to read '18K HGE' (Heavy Gold Electroplate), indicating the piece is high-quality costume jewelry rather than solid gold. The design aesthetic is characteristic of the late 20th century, approximately the 1970s or 1980s, leaning toward a bold, mid-century modern influence. Condition-wise, the gold plating shows significant wear and thinning, especially along the bottom of the shank and the edges of the setting where the base metal is beginning to show through. There is minor surface scratching on the onyx, common for its age, though no major chips are present. The craftsmanship is typical for mass-market fashion jewelry of that era, utilizing a cast assembly method.