How to tell if vintage jewellery is valuable
Turn the piece over first. Almost everything that determines value in vintage jewellery is on the back: the hallmark, the clasp, the finish of the setting and the maker's mark. The front is designed to be looked at; the back is where the manufacturing honesty is, and a dealer valuing a lot spends most of their time there.
1. Look for a hallmark
925 or 'sterling' means sterling silver. 800 and 835 are continental European silver standards, common in older Spanish, German and Italian pieces. 9ct, 375, 585, 14k, 750 and 18k are gold. 'Silver tone', 'silver plated', EPNS and a bare absence of any mark all mean base metal. Marks live on clasps, the inside of a band, the back of a pendant bail and the post of an earring — a loupe or a phone camera at maximum zoom is enough.
2. Date it by the clasp and the findings
The fittings date a piece more reliably than the style, because style gets revived and fittings don't. Screw-back earrings point to pre-1950s. Clip-backs run from the 1930s to the 1970s. Butterfly backs on pierced earrings become common from the 1960s. A C-clasp on a brooch suggests pre-1920s; a trombone clasp is European and mostly pre-1950; a modern roll-over safety catch means later. None of these are hard dates on their own — they narrow the range.
3. Read the construction
Individually set stones with prongs, foil-backed stones in closed settings, articulated links that move independently, and any hand-finished detail on a surface nobody sees: all signs of cost. Glued-in stones, a moulded seam running through the design, and light hollow weight point the other way. Weight is informative in the hand — quality costume jewellery from the mid-century is usually heavier than a modern reproduction of the same look.
4. Find the maker
A signature multiplies value more than the material does in costume jewellery. Trifari, Coro, Sphinx, Monet, Napier, Sarah Coventry, 1928, Avon and Exquisite turn up regularly in European estate lots and all have collectors. The mark is usually on the reverse near the clasp, sometimes on a small applied plaque. An unsigned piece is not worthless, but a signed piece is far easier to value and to sell.
5. Know what does not add value
Age alone. Old and ordinary is still ordinary, and most house clearances are 90% ordinary. Damage that involves a missing stone, a repaired shank or a replaced clasp cuts value hard — often to nothing on a costume piece, because the repair costs more than the piece. Patina is different: tarnish on silver is surface and comes off, and a soft darkening in the recesses of a cast piece is usually original and desirable.
Where this leaves a jar
This is exactly the sorting we do before a jar is filled, which is why our jars list what they contain and not what they might contain. Every piece has been turned over, the marks read, the broken ones pulled. What you are buying is the sorting as much as the jewellery.
The dealer's notes
Does a piece with no hallmark have no value?
No. Costume jewellery is rarely hallmarked and some of the most collected makers marked inconsistently or only on a paper tag that is long gone. A missing hallmark rules out precious metal, not value.
What is estate jewellery?
Any jewellery that has had a previous owner, regardless of age. It is a sourcing description, not a quality or era one: an estate lot can contain an eighteenth-century ring and a 2015 high-street necklace in the same box.