Identifying authentic medieval gold coins requires a keen eye and familiarity with medieval minting practices. First, examine the coin’s weight and size. Medieval gold coinage followed strict regional and temporal weight norms. The standard weight of a Byzantine solidus was about 4.5 grams, while a Florentine florin was about 3.5 grams. Substantial discrepancies from established weights often suggest a contemporary fake.

Next, inspect the design and engraving. Genuine coins display subtle flaws due to manual die striking, such as off-center strikes or uneven relief. Modern fakes lack the organic imperfections of authentic hand-struck pieces. Look for wear patterns consistent with age and circulation. Authentic pieces show smooth, gradual erosion on raised elements like the monarch’s portrait or crown, fraudulent coins may have surface wear that looks forced, patchy, or chemically induced.

Test the coin’s metallic content. Authentic medieval gold typically contained 90–98% fine gold. Modern counterfeits may use lower purity gold or even gold-plated base metals. Laboratory testing via X-ray fluorescence or fire assay provides definitive results. But a simple magnet test can help rule out iron-based fakes since real gold is not magnetic.

Examine the inscribed legends. Medieval coins often feature Latin or regional scripts that follow specific conventions of the era. Look for spelling errors, inconsistent letter shapes, or anachronistic symbols. A coin purporting to be from the 1100s with 1400s-style lettering is almost certainly a modern forgery.

Evaluate the coin’s surface aging and corrosion. Over time, real coins develop a stable, matte patina with subtle color variations. Be suspicious of coins that appear freshly cleaned, buffed, or coated with lacquer or chemicals. Also, be wary of coins that appear too clean or lack any signs of soil or corrosion if they are claimed to have been unearthed.

Research the provenance. Coins backed by verifiable records from established institutions carry higher credibility. Be skeptical of coins offered without documentation or from sellers with no reputation in numismatics. Legitimate sellers include certification documents and cross-references to scholarly coin catalogues.

Finally, consult experts. Never guess—consult a professional with expertise in medieval coin authentication. Experts can match it against verified specimens and employ microscopes, spectroscopy, or アンティークコイン投資 metallurgical analysis to spot modern forgeries. Because authentic pieces are both rare and highly prized, thorough verification is a non-negotiable step in acquisition.