Marquise Cut Black Stone Gold Tone Ring

This item is a ring featuring a prominent marquise-cut black stone set in a gold-toned metal band. The stone measures approximately 15-20mm in length, and is a deep, opaque black, with a polished, reflective surface. Given the visual information, it is highly likely to be onyx or black tourmaline, as opposed to jade as indicated in the additional context, which typically presents with a more translucent appearance or distinguishable fibrous texture, even in its darkest forms. The stone is horizontally oriented on the finger. It is securely held by a bezel setting at each pointed end, which appears to be crafted from the same gold-toned metal as the band. The band itself exhibits a decorative, possibly filigree or sculptural, pattern on the shoulders leading up to the stone setting, indicating a level of craftsmanship beyond a simple plain band. The metal shows some areas of wear or slight discoloration consistent with age and use, suggesting it might be gold-filled, plated, or a lower karat gold alloy, rather than solid high-karat gold. There are no immediate visible signs of damage such as chips or cracks on the stone, and the overall condition appears good for an item that has been worn. The style suggests it could be from the mid-20th century, possibly 1950s-1970s, a period when bold, individual stones and intricate metalwork were popular. No specific maker's marks or signatures are discernable from the provided image.