Emerald-Cut Dark Blue Sapphire or Synthetic Spinel Pendant Necklace

This piece of jewelry features a large, emerald-cut focal stone that is a saturated, midnight blue in color. Based on the deep hue and visible light reflections, the stone may be a dark natural sapphire, a synthetic sapphire, or a midnight blue synthetic spinel. It is secured in a classic four-prong basket setting, likely crafted from yellow gold or gold-toned metal, though no hallmarks are visible in the image to confirm purity (e.g., 14K or 18K). The pendant is suspended from a delicate, fine-link chain, possibly a box or snake chain style, which appears to be in good functional condition. The stone exhibits sharp facets and a clean face, suggesting it has been well-maintained with minimal surface scratching. The overall aesthetic is consistent with mid-to-late 20th-century jewelry design, emphasizing a bold, singular gemstone. The craftsmanship is professional, with the basket setting neatly surrounding the stone's perimeter. There are no obvious signs of heavy wear, tarnish, or repair, though a detailed inspection under magnification would be required to identify internal inclusions or micro-abrasions that would further determine the stone's origin and exact value.