Tiffany & Co.
generalDate code & serial
Tiffany does NOT use a public serial/date-code system on most silver and jewellery the way watch or bag brands do. Authentication rests on the HALLMARK STACK: a metal-purity mark plus the maker/brand mark, often plus a designer signature. Purity marks seen on genuine pieces include '925' or 'STERLING' (sterling silver, 92.5%), '750' (18K gold), and platinum marks such as 'PT950'/'950'. Brand marks have varied over the decades and appear as formats like 'T&Co.', 'TIFFANY & CO.', 'Tiffany & Co. 925', or 'Please Return to Tiffany & Co.' Designer lines carry an added engraved signature — e.g. Elsa Peretti, Paloma Picasso, Jean Schlumberger ('Schlumberger', 'Schlumberger Std.', 'Schlumberger Studios'), Frank Gehry, Angela Cummings. Some diamond engagement pieces carry a laser-inscribed diamond/ring serial that can in principle be checked against Tiffany records, but this is piece-specific, not a universal code, and verification generally requires Tiffany's cooperation.
What to checkRead the full hallmark stack under loupe/magnification: (1) is a purity mark present and does it match the metal (XRF-confirmable); (2) is the brand mark crisply and evenly struck with correct capitalisation ('Tiffany & Co.' with capital T and C); (3) if a designer line, is the signature spelled and stylised correctly (e.g. Peretti's dotted 'i', correct Schlumberger variant). Cross-check the mark format against the era/collection the piece claims to be. Treat any single mark as guidance, never a verdict — high-end fakes now reproduce crisp, correctly-spelled marks, so confirm metal by XRF and corroborate with construction, finishing and, where possible, provenance.
Red flags & tells
Blurry, shallow, or mushy stamp
generalAuthentic Tiffany marks are typically sharply struck — clean, crisp, evenly spaced. Soft/rounded 'mushy' marks can indicate a cast copy taken from a mould, and uniform shallow etching can indicate a laser-etched counterfeit. A blurry or hard-to-read stamp is a warning sign, but treat it as directional: good fakes now reproduce sharp-looking marks, and some genuine older or worn pieces can look soft, so never judge on strike quality alone.
Wrong font, spacing, or capitalisation
generalIrregular letter spacing, incorrect fonts, run-together words (e.g. 'PLEASERETURNTO' with no proper spacing), misspellings, or lowercase where capitals belong ('Tiffany & Co.' should have capital T and C). Malformed numerals (an '8' rendered as blobs rather than clean loops) are a tell. Because the correct spacing/capitalisation is well documented, better counterfeits copy it — a mark that passes this check is not proof of authenticity.
Missing or mismatched purity mark (XRF disagreement)
reliableGenuine silver carries '925' or 'STERLING'; gold '750'; platinum a platinum mark. An absent purity mark, or a stamped purity that does not match the actual metal measured by XRF, is a strong red flag. The XRF-vs-stamp mismatch is the decisive part; a merely absent mark can also occur on legitimately worn or altered pieces, so corroborate.
Misspelled or wrongly stylised designer signature
generalPeretti, Picasso, Schlumberger, Gehry (and Cummings) lines each have a correct signature. Misspellings, wrong stylisation, or a designer signature on a form that designer never made point toward a fake. Note the specific stylisation cues (e.g. Peretti's dotted 'i', Schlumberger variant) are guidance reported by authenticators, not an official published standard, and skilled fakes copy them.
Poor construction and finishing
generalVisible casting sprues, rough solder joints, crooked/open jump rings, concealed seams, unsoldered chain links showing a join line, uneven stone setting, and sloppy finishing on undersides. Genuine Tiffany chain links are usually soldered so joins look seamless — but link style varies by collection and era, so use as a cue, not a rule.
Feels too light for its size
uncertainSolid sterling and gold are dense; a piece that feels surprisingly light or flimsy may be a cheap alloy or hollow construction. This is only a directional cue alongside XRF — many good fakes are made in solid sterling and will pass a weight impression (and XRF for silver content), so weight alone proves nothing.
Wrong or off packaging
uncertainIncorrect boxes and pouches with inaccurate fonts or colours accompany many counterfeits, but packaging supports and never proves authenticity — genuine pieces are often resold without original packaging, and counterfeit packaging is widely reproduced.
The honest caveat
CAVEATS: Tiffany hallmark styles have changed across decades (T&Co. → Tiffany & Co. → Please Return to Tiffany & Co.), so a mark format that looks 'wrong' may simply reflect a different era — cross-reference before judging, and avoid absolutes like 'authentic Tiffany never used X'. No universal serial/date code exists for most silver and jewellery, so authentication depends on the combined hallmark + metal + construction picture, not one mark. Superfakes increasingly defeat single tells: high-end counterfeits reproduce crisp die-struck-looking marks, correct capitalisation and spacing, and even solid sterling weight (which XRF will pass on silver content), so weight and stamp-sharpness alone are insufficient — corroborate with designer-signature micro-detail, hidden-surface finishing, and, where possible, provenance/serial verification with Tiffany. Note the designer-signature micro-cues (Peretti's dotted 'i', etc.) are authenticator/collector guidance, not an officially published standard. Everything here is general guidance to assist a human authenticator, not a standalone pass/fail. Sources: TheRealReal authentication guide, Gray & Sons, Precious Metals Refinery, Vantier House hallmark guide, Signed Vintage Jewelry (Peretti). Secondary sources (DJR Authentication Vol. 89, Suttons & Robertsons, Diamond Banc) cited by the junior note were not independently re-verified here.