Mid-20th-century style pendant with blue stone in a crown-style setting

This item appears to be a pendant featuring a large, oval-cut stone of a pale lilac or blue-grey hue. The gemstone is held in an ornate metal setting that is stylistically consistent with crown or buttercup-style mountings popular in mid-20th-century costume jewelry. The mount features multiple decorative prongs or 'petals' ending in rounded, ball-like tips. This metalwork appears yellow-toned, possibly gold-plated or brass, though it exhibits significant darkening and what may be surface oxidation or patina, particularly in the recessed areas. The owner identifies this piece as originating from the 1950s-1970s, a timeframe consistent with this style of prominent prong setting, though this remain unverified without physical inspection of hallmarks. The stone shows some surface wear and minor abrasions consistent with use. Attached to the pendant is a fine-link silver-toned chain, possibly a later addition as it contrasts with the warmer tone of the pendant housing. No maker's marks or metal purity stamps are legible in the provided image, necessitating a hedged identification based solely on visual aesthetics and construction style.

Based on my visual analysis of the provided image, this pendant appears to be a mid-20th-century style costume piece featuring a crown or ‘buttercup’ prong setting. Per user submission, the item is identified as originating from the 1950s–1970s. While the decorative metalwork is consistent with the aesthetics of that era, I cannot confirm the metal purity or the specific nature of the stone from a photograph. The visible darkening and potential oxidation suggest a base metal or gold-plated brass rather than high-karat gold, and the stone possesses a hue often associated with synthetic spinel or glass common in period costume jewelry. I cannot verify the presence of hallmarks or maker's marks, which are essential for a precise attribution. The value estimate of $45–$125 assumes the item is a quality vintage costume piece in good collectible condition. If physical inspection were to reveal hallmarks for precious metals (such as 14k gold) or if the stone is determined via gemological testing to be a natural sapphire or rare spinel, the value could increase significantly into the $300–$600 range. Conversely, if it is a contemporary 'in the style of' reproduction using modern alloys, the value would likely sit below $20. To establish a more precise valuation, a physical examination is required to check for stamps on the pendant and chain, perform a professional acid test for metal content, and conduct a refractometer test on the gemstone. The market for mid-century costume jewelry remains steady, with value driven primarily by the intricacy of the setting and the reputation of the manufacturer, should one be identified.