Authenticating Luxury Jewellery: Hallmarks, Engravings, Quality

On a precious-metal piece, the title hallmark guarantees the metal's content. In France, the eagle's head has historically marked 18-carat gold (750 ‰), with specific hallmarks for platinum and silver. The maker's mark, diamond-shaped, identifies the manufacturer or house that stands behind the piece. These hallmarks are tiny but crisp, struck deeply, usually on the clasp, the bail or the inside of a bangle.

A note of caution: luxury costume jewellery (gilt metal, like most Chanel pieces) carries no title hallmark, which is normal and does not disqualify it — you then rely on the signature and the other criteria. Conversely, the absence of a hallmark on a piece sold as solid gold is a major red flag.

Every great house signs its pieces. Cartier engraves "Cartier", a unique serial number and, often, the metal mark and a reference code; on Love and Trinity rings, the engraving is crisp, even and aligned. Van Cleef & Arpels signs "VCA" with a number and hallmark. Chanel engraves "CHANEL", often with a serial number, country mark and season code on recent pieces.

Examine the engraving with a loupe: on an authentic piece, it is deep, even and perfectly aligned, with consistent typography. Counterfeits show shallow engravings, irregular letters, approximate spacing or spelling errors. Also check that the serial number is consistent with the era and the model.

The metal of a great house is heavy, dense and impeccably finished: no burrs, no sharp edges, an even surface. A piece that is abnormally light, or whose gilding flakes quickly, should arouse suspicion.

For set pieces, the setting is telling: the stones are perfectly calibrated, aligned and firmly held — none moves or rings hollow. On diamonds, you assess the 4Cs (carat, colour, clarity, cut). On costume jewellery, you check the regularity of the pearl strand, the deep brilliance (never "plastic") and the crispness of the enamel. A sloppy finish almost always betrays a copy.

Every piece of jewellery that joins our selection is examined by our experts: hallmarks, signatures, engravings, quality of the metal and setting, and consistency with the production era. Every validated piece is sold with a certificate of authenticity, and shipping is complimentary.

For many items, we also rely on Entrupy, an authentication solution using artificial intelligence and microscopy recognised across the luxury industry, which issues a certificate of authenticity. Entrupy authentication is used on a large number of pieces and remains available on request. It is this twofold guarantee — expert eye and technology — that lets you buy with confidence.

Buy with peace of mind: discover our authenticated, certified pre-owned luxury jewellery, from Chanel sautoirs to the Cartier universe. Learn more about our authentication.