How to Authenticate 18k Italian Gold Jewelry:
A Professional Forensic Guide

Every genuine piece of 18k Italian gold carries a small stamp on its metal. This is how to authenticate 18k Italian gold jewelry from scratch, using the hallmark system, one physical test and the kind of documentation only legitimate sellers can provide.

Italian province codes: reading the full hallmark on Italian gold

The 750 stamp doesn't appear alone. Next to it, you'll find an official mark from the assay office that verified the piece: a stylised star alongside two letters identifying the Italian province where the work was certified. This is what distinguishes gold actually verified in Italy from pieces marketed as Italian without that paper trail.

A piece with a two-letter Italian province code next to the 750 mark has passed through state verification in Italy. That's the chain of custody worth confirming before purchase.

"The stamp is not decorative. It is the signature of a government official, backed by EU law, placed on the metal before it was ever offered for sale."

The magnet test: the fastest physical check for genuine 18k gold

Gold is not magnetic. Neither is any genuine 18k alloy: the copper, silver and palladium used to reach 18k purity are all non-ferromagnetic at these proportions. Hold a strong magnet near a piece of solid 18k gold and nothing happens.

If the piece pulls toward the magnet, it contains steel or iron at its core. That means it's gold-plated or gold-filled, not solid 18k gold, regardless of what the seller has said.

This test takes ten seconds and costs nothing. It won't catch every type of fraud, since some base metal alloys are also non-magnetic, but it reliably eliminates the most common category of fake: a heavy plated piece designed to feel substantial.

Weight and surface: what genuine 18k Italian gold looks like up close

18k gold has a density of about 15.6 g/cm³. Gold-plated brass sits around 8.5 g/cm³ at the same visible volume. A piece that looks large but feels light relative to its size is worth questioning. This is not a laboratory test. It's a trained feeling that becomes instinctive after handling enough genuine pieces.

Surface examination under magnification tells you more. Solid 18k gold holds consistent colour across the entire piece, including at corners, inside engraving channels, and at points of friction. Plated pieces lose their colour coating where the metal rubs against skin, fabric, or other surfaces. Check the inside of ring bands. Check clasp edges. Check the bail of a pendant, where a chain runs through repeatedly.

Florentine goldsmithing has a specific signature worth knowing: bulino, or burin engraving, produces hand-cut lines with slight variation in depth and width. Machine engraving is mechanically uniform. If a piece is sold as Florentine hand-engraved work, look for that human irregularity in the linework. Its absence on a claimed hand-engraved piece is a reason to ask harder questions.