Vintage/Antique Filigree Cocktail Ring with Purple Stone

This is an antique or vintage cocktail ring, likely made of sterling silver or a similar base metal given its tarnished appearance and intricate filigree work. The ring features a prominent, oval-cut synthetic or natural purple stone, possibly amethyst or a faceted glass/resin imitation, set within an ornate bezel. The stone exhibits several facets and a deep, translucent purple hue, with flashes of lighter purple or magenta observable through its facets. The metalwork around the stone displays intricate filigree and granulation techniques, characterized by twisted wire accents and small raised beads. Several scroll-like elements and open-work patterns form the gallery of the ring below the main setting, giving it an airy and decorative feel. The metal has a significant dark patina, consistent with age and oxidation of silver, suggesting it has not been recently polished. There are no immediately visible maker's marks or hallmarks in this view, which would typically be on the inner band. The band itself is not fully visible but is described as adjustable, which might indicate a later alteration or a common feature for fashion rings of certain periods. The overall craftsmanship suggests a piece from the late 19th to early 20th century, possibly Art Nouveau or Edwardian era, given the elaborate and organic-inspired filigree, although without clearer identification of the stone and metal, it could also be a later, perhaps mid-20th century, reproduction or fashion piece. The piece appears to be in good condition for its age, though the extent of the patina could be considered a condition issue by some, while others might value it as part of its antique charm. No obvious chips or cracks are visible on the stone, nor are there signs of major repairs or missing elements in the metalwork.