An expert’s guide to signed jewellery

Christie’s Senior International Jewellery Director David Warren explains why pieces featuring the signature of top brands attract serious collectors worldwide

What is signed jewellery?

Signed jewellery indicates the name of the jewellery house or maker with an engraving on the underside of the piece or the inside of a ring. Jewellery makers began signing their work during the Arts & Crafts and Art Nouveau periods, from about 1860 onwards. An early instance is René Lalique, who always signed his work. The practice was popularised in the 20th century, when all the top jewellers and many small ateliers began applying their signatures to their jewellery. 

An example of a Cartier signature
An example of a Cartier signature

Is signed jewellery more valuable than unsigned jewellery?

Generally, yes. If it is one of the top makers, a signature can add 50, 100 or even 300 per cent to the value. Christie’s jewellery specialist David Warren recalls seeing a bracelet from the 1920s — an attractive and slightly unusual design — that had been estimated some years earlier at £8,000 to £12,000. After a great deal of scrutinising, Warren discovered what appeared to be remnants of ‘Van’ from a Van Cleef & Arpels signature. A photograph was sent to the company, which confirmed and precisely dated the piece. The bracelet turned out to be a rare example from the much sought after Art Deco period and subsequently sold for £250,000, with premiums. 

A jadeite, onyx and diamond bracelet, by Oscar Heyman & Brothers. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $150,000

A jadeite, onyx and diamond bracelet, by Oscar Heyman & Brothers. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $150,000

Are some signatures more valuable?

Cartier, FabergéHarry Winston, JAR, Lalique, Van Cleef, to name a few — any of those names on a jewel will transform the value of the piece,’ says Warren. ‘Jewellery designed and produced by these makers represents a very high standard.’ That said, much depends on the piece. Cartier was such a prolific producer, for example, that a signature on traditionally-designed items will improve the value, but not necessarily dramatically. A signature on a 1920s Cartier ‘Tutti Frutti’ piece — the most sought-after of the brand’s products  — however, can potentially transform the value to millions of dollars. 

A coloured sapphire, coloured diamond and diamond ring, by Oscar Heyman & Brothers. A coloured sapphire, sapphire and diamond ring, by Oscar Heyman & Brothers. These lots were offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $100,000 and $35,000 respectively

A coloured sapphire, coloured diamond and diamond ring, by Oscar Heyman & BrothersA coloured sapphire, sapphire and diamond ring, by Oscar Heyman & Brothers. These lots were offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $100,000 and $35,000 respectively

Is all signed jewellery collectible?

No, not all signatures enhance the value. With signed pieces, the particular maker and period are important. For jewellery from top brands, the signature provides a level of comfort in terms of quality. ‘With a 20th-century signed piece from manufacturers such as Boucheron, Bulgari, Cartier, Chaumet, Fabergé or Van Cleef & Arpels, you know that the piece will be of a high standard in terms of design, quality of stones, and the way in which it has been made,’ confirms Warren.

An example of a Boucheron signature
An example of a Boucheron signature

How do I know if a signature is authentic?

Warren recommends that budding collectors purchase a jeweller’s loupe (10 x magnification) and start training their eye by examining pieces. ‘View the signature through the loupe. A fake signature might look as though it was engraved yesterday, with the writing very bright and shiny, which doesn't really sit with the age of the piece,’ he explains. ‘Also, learn to recognise the way different houses signed their work. In early Cartier pieces, for example, there is often a faint line, which they drew before writing Cartier neatly on top.’

If the jewellery is not signed, does that mean it's not genuine?

With time, signatures can rub away or become illegible. Warren once examined an emerald necklace that appeared to be Cartier but which had no signature. After a lot of close examination, he discovered what looked like extremely faint letters spelling ‘Par’ and possibly a ‘C’. Because Warren believed the jewel was by Cartier, the owner went to the company, which found the necklace in its archives. It had originally been signed ‘Cartier Paris’ and sold for $3 million. If it hadn't had the signature or been traced to Cartier, Warren says the necklace would have sold for approximately half this sum. 

If there is no information regarding an item’s provenance, the rule of thumb is to assume the piece is ‘wrong’ until proven right. If its value is a few hundred pounds, the ramifications of a mistake are fewer. But for a more valuable item, the buyer should carefully review the provenance and must trust the reputation and authority of the seller.

In terms of value, does the period matter?

There are always exceptions that break the rule, but generally the Art Deco period generates most interest, followed by Belle Epoque, Retro Period, Art Nouveau and Arts & Crafts.

An emerald, pearl and diamond flower brooch, by Cartier. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $487,500

An emerald, pearl and diamond flower brooch, by Cartier. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $487,500

Will the age of the piece affect the value?

Value does not depend as much on the age of the piece as its maker, but it is important to confirm the piece is authentically from the period and not a modern, or older, reproduction. As an example, jewellery might be modern and made in the Art Deco style. ‘You must trust the person who is selling the piece or ask for a written receipt that documents the dates. In that case, if there were to be a genuine mistake, a refund could be made,’ Warren says.

What else should be considered?

Make sure the jewellery has not been embellished. ‘I occasionally find pieces that have been “glamourised” by adding extra gemstones. This can falsely increase the value if the piece if undetected,’ says Warren. Even signed, the item is no longer in original condition and its value is diminished. Some jewels have been altered for practical reasons, such as a repair; a long necklace might have been divided and made into several shorter necklaces, thereby decreasing its value. 

What are some notable Christie's signed jewellery sales? 

In 2013 a signed Art Deco ‘Tutti Frutti’ bracelet by Cartier sold for $2 million in New York. The exceptional piece featured diamonds, jadeite and gemstones. Specific signed jewels that we have sold for record prices recently include a Belle Epoque devant-de-corsage brooch by Cartier, which in 2014 achieved $17.4 million and became the most expensive signed jewel ever auctioned. A gold and diamond bangle by the highly sought after contemporary jeweller JAR realised $3.5 million in a recent auction at Christie’s.

A diamond cluster necklace, by Harry Winston and a photograph, by Cecil Beaton. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $1,027,500

A diamond cluster necklace, by Harry Winston and a photograph, by Cecil Beaton. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $1,027,500

Does Christie's offer a wide range of signed jewellery? 

Pieces of signed jewellery are offered in all of our jewellery auctions. On occasion, Christie’s has organised themed sales of signed jewellery, including several auctions devoted entirely to Cartier, a centenary celebration auction on behalf of Van Cleef & Arpels, and special auctions of Asprey & Garrard, Bulgari and Lalique. In 1997 the highly popular Bijoux Signes sale was a dedicated signed jewels auction with 150 pieces. the catalogue was produce in collaboration with fashion designer Hubert de Givenchy, with the jewels photographed on many of his dresses, including the simple black dress he designed for Audrey Hepburn in Breakfast at Tiffany’s

A pair of blue opal, multi-coloured zircon and diamond ear pendants, by JAR. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $223,500

A pair of blue opal, multi-coloured zircon and diamond ear pendants, by JAR. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $223,500

Which signed jewellery is currently most popular among collectors?

Signed pieces by Cartier, Van Cleef & Arpels and Harry Winston are highly desirable, and contemporary pieces from designers such as Viren Bhagat, Wallace Chan, Edmond Chin and JAR attract strong followings and fetch considerable sums at auction. Some of the many makers that enjoy a strong following include Belperron, Boucheron, Bulgari, Chaumet, Schlumberger, Tiffany, Webb and Yard

The bracelet below is by New York firm Oscar Heyman & Brothers, founded in 1912. The brand is renowned for its use of coloured gemstones, creating pieces from vibrant stones including tourmaline, garnet, peridot, jade, and sapphires of almost all colours. A fantastic collection of Oscar Heyman & Brothers jewels is a highlight of our 7 December Magnificent Jewels sale.

An Art Deco emerald, ruby and diamond bracelet, by Oscar Heyman & Brothers. Estimate $40,000-60,000. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $223,500

An Art Deco emerald, ruby and diamond bracelet, by Oscar Heyman & Brothers. Estimate: $40,000-60,000. This lot was offered in Magnificent Jewels on 7 December 2016 at Christie’s in New York and sold for $223,500

How should a new collector of signed jewellery begin?

There are many ways to build a signed jewellery collection, whether by period, such as Art Deco, or a particular article of jewellery, such as cufflinks or animal designs. ‘It makes the most sense to go for a maker or a period, or it could be both — such as Art Deco jewellery made by Cartier in the 1920s, one of the most creative moments in its history,’ suggests Warren.

Stick closely to the theme or period and curate the collection thoughtfully. Pieces should complement each other so that they can be worn together for a more impressive effect; this will also add value. 'If it becomes a good investment, that's great news,’ he concludes. ‘But buy the pieces you love.’

Follow us on Instagram for regular jewel updates