This vintage open-heart pendant necklace featuring a border of prong-set ruby gemstones on a fine chain.
The "925" stamp stamped onto the metal bail indicates that your necklace is made of sterling silver.
Sterling silver is an alloy composed of 92.5% pure silver mixed with 7.5% other metals (usually copper) added for durability. The gold coloration visible on the piece suggests that it is vermeil—sterling silver that has been plated with a layer of gold—or that it has simply tarnished over time, giving it a warm, antique patina.
The secondary stamp located below the gemstones reads "THAILAND", which identifies the country where the jewelry piece was manufactured.
Based on this close-up image, the gemstones are highly likely to be natural commercial-grade rubies rather than cubic zirconia or flawless lab-grown stones.
Looking closely at the facets and clarity of the stones under this lighting, several distinct visual characteristics point away from CZ:
Translucency & Milkiness: The stones have a slightly sleepy, milky, or silky appearance rather than the glass-like, crisp transparency typical of red cubic zirconia.
Visible Inclusions: Several of the stones show internal structures, slight variations in color depth, and microscopic fissures or "silk" (natural microscopic inclusions) that are characteristic of natural corundum (ruby).
Surface Texture: The facet edges and faces show subtle natural texture and wear patterns common to lower-to-mid-grade genuine rubies that have been mined, cut, and likely heat-treated or glass-filled to improve their color.
Secondary Market Price ($25 – $40): If sold as an unbranded, pre-owned item on secondhand platforms like eBay or at a local estate sale, unbranded vintage Thai 925 heart pendants typically fetch around this amount.
Mid-Range Retail Price ($50 – $150): If the piece features a recognizable vintage maker's mark (such as certain designer signatures stamped next to the 925 mark) or is sold by a curated vintage boutique on platforms like Etsy, prices frequently land in this tier.
The Gemstones: Because these are likely genuine commercial-grade rubies, they hold a slight value premium over cubic zirconia fashion jewelry, but because they are heavily included/cloudy, they do not command the high per-carat prices of investment-grade gems