Pendant with violet-hued stone in buttercup-style setting

This item appears to be a faceted round stone pendant, featuring a violet or lavender hue, mounted in a crown-style or 'buttercup' prong setting. The center stone is held by multiple small prongs visible around its circumference, which is stylistically consistent with the mid-20th-century jewelry designs described in the unverified owner's notes as 1950s-1970s. The stone exhibits a large table and geometric faceting that suggest it could be glass, synthetic spinel, or a colored gemstone, though the exact material cannot be determined without physical refraction testing. The setting appears to be a yellow-toned metal, possibly gold or gold-plated, attached to a fine-link silver-toned chain. There are no visible hallmarks, maker's marks, or purity stamps legible in the image, meaning any attribution to a specific manufacturer or metal composition is a hypothesis only. Condition-wise, the stone appears intact with no major visible chips or fractures, though the depth of the metal patina is difficult to gauge due to lighting. The crown-style setting exhibits craftsmanship consistent with mass-produced or semi-custom jewelry from the mid-to-late 20th century.

Based on my visual analysis of the provided image, this pendant is consistent with mid-to-late 20th-century 'costume' or semi-fine jewelry. The owner identifies this as a 1950s–1970s piece, which aligns with the buttercup or crown-style setting visible. While the violet stone displays attractive faceting, I cannot verify its composition from a photo; it could be amethyst, synthetic spinel, or glass. Physical testing for refractive index and hardness would be required to confirm the material. Further, I can see what appears to be a yellow-toned setting on a silver-toned chain, but without visible hallmarks, I cannot assume the metal purity. The estimated market value assumes the piece is a well-preserved example of mid-century costume jewelry or low-karat gold. If authorized testing were to reveal the setting is solid 14k gold and the stone is a natural high-grade amethyst, the value could increase toward the upper end of the range ($120+). Conversely, if the metal is a base-metal alloy and the stone is glass, the value would likely sit at the lower end ($20–$45). Generally, there is steady demand for vintage mid-century pendants due to their classic design, though mass-produced items of this era without a designer mark have a saturated secondary market. To confirm these hypotheses, an in-person inspection of the metal and stone by a certified gemologist is recommended.