Gold Hallmark Identifier
Decode gold purity markings by interpreting hallmark stamps, karat values, and millesimal fineness numbers. Convert between karat, millesimal fineness, and gold percentage with country-specific hallmark symbol lookup.
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Common uses
Jewelry buyers verify purity before purchase. Gold investors compare purity across countries. Sellers estimate scrap value using weight × purity. Collectors identify antique hallmarks from UK, France, and India.
How gold purity is calculated
Karat is the ratio of pure gold to alloy metals, measured on a scale of 24 (pure gold). Millesimal fineness is parts per thousand — 750 means 750 parts gold per 1000 total. To convert: karat × 1000 ÷ 24 = millesimal; millesimal × 24 ÷ 1000 = karat; karat × 100 ÷ 24 = percentage.
Fun Fact: Pure gold (24K) is so soft it can be molded by hand — that's why jewelry is almost always alloyed with other metals. The term "karat" comes from the carob seed, which was historically used to measure gold purity because of its consistent weight.
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