Bulgari Tubogas Necklace (vintage 18k gold)

From gas pipe to gold

The word Tubogas comes from the French tube de gaz, a gas pipe. The technique was developed in the 19th century to make flexible metal hose: narrow strips of metal are coiled around a central core, usually copper or wood, and the core is then removed, leaving a hollow tube that bends and twists without a single solder joint. Bulgari's own history puts it plainly: the motif was inspired by the shape of the gas pipes in use from the 1920s onward, and the technique dates to the second half of the 19th century.

Who first turned it into jewelry is not known. The French jeweler and historian Henri Vever credited early experiments to Auguste Lion in the late 19th century, though scholars treat that claim with caution. What is certain is that it was an industrial process adopted directly by goldsmiths, not just an industrial look.

Bulgari's accounts of its own timeline differ slightly. The house's official history says Bulgari revived the technique in the 1970s and made it a trademark. Its archive director, Gislain Aucremanne, told a Geneva audience in 2025 that Tubogas became central for Bulgari in the 1940s, when platinum was requisitioned for the war and jewelers fell back on gold, producing bold plain coils, some framing watch dials. Both agree the 1970s were when Tubogas necklaces became a Bulgari signature.

The Bulgari brothers' gold

Sotirios Voulgaris, a Greek silversmith, arrived in Rome and opened his own shop in 1884, Italianizing his name to Bulgari; the logo uses a classical Roman V in place of the U. His sons Constantino and Giorgio took over after his death in 1932, and the house hit its stride in the dolce vita years of the 1950s and 1960s under the founder's grandsons Paolo, Gianni and Nicola, who moved away from demure French styles toward bold yellow gold and colored stones.

Gianni Bulgari described the shift that made Tubogas so popular. Speaking in 1970, he said people 'no longer want something they put on or carry for great occasions, but jewellery they wear often with many things.' Simple gold coils that went from office to dinner suited that idea exactly.

In the 1960s and 1970s Bulgari pushed the technique further. It worked gold in yellow, rose and white for striped effects, fused steel with gold, joined several rows of Tubogas into wide collars, and set coils with cabochon gems, antique intaglios and cameos. The Monete jewels placed real Greek and Roman coins in flexible Tubogas mounts, a nod to the family's Greek roots in Rome. Bulgari's archive shows a steel-and-gold Tubogas choker and bracelet made in 1982 to 1984.

Gold for every day

Tubogas necklaces belong to a decade when gold itself was changing. In August 1971 the United States ended the direct convertibility of the dollar to gold, effectively bringing down the postwar Bretton Woods currency system, and Arab oil producers imposed an embargo in October 1973. Yellow gold became something to wear daily, not just to keep.

The same years brought Bulgari to a global audience. The house opened in New York and other fashion capitals, and the snake watches with Tubogas bands, sister pieces to the necklaces, starred in its 1970s advertising. Andy Warhol, a regular visitor to the Rome store, compared Bulgari's jewelry to contemporary art and owned a triple-coil Tubogas snake watch-bracelet.

On the market today

Because these are serial pieces rather than unique jewels, vintage Tubogas necklaces trade regularly at auction and through dealers, and the multi-row collars bring the most. On April 20, 2023, a Bulgari triple-row Tubogas necklace in 18-karat yellow gold, about 13 inches long and weighing 199.70 grams, sold at auction in the United States for $35,000 against an estimate of $12,000 to $15,000.

On December 4, 2024, a signed triple-row necklace of flattened Tubogas chains in 18-karat gold, with a 13-inch inner circumference, sold at auction in the United States for $37,800, more than double its $18,000 to $22,000 estimate. A New York dealer was asking $34,000 in October 2026 for a double Tubogas necklace in 18-karat gold made around 1970.

Gem-set examples go far higher. An emerald and gold Tubogas necklace signed Bvlgari, 15 inches long and centered on a Zambian emerald, sold in an online sale in March 2024 for $189,000. A bicolor Tubogas collar from the 1970s sold at auction in England for £37,700.

How to tell a real one

The test is in the hand. As Bulgari's archive director put it, the marvel of Tubogas is 'not in what one sees, but in what one feels': a genuine piece springs and contracts, while a copy feels rigid and dead. Bulgari describes its Tubogas as a flexible band with rounded contours, made without soldering and requiring hours of specialist work.

Look for a Bulgari or Bvlgari signature, and for collars that wrap the neck without a conventional clasp. Weight is part of the appeal: the triple-row collars cited above weigh roughly 200 grams.

Vintage pieces come in many variations, from single plain coils to stacked rows, yellow and white gold stripes, steel accents, and coin or gemstone centers. Coin pieces form their own collecting category under the Monete name.

A coil that never left

Tubogas became so central to Bulgari that it shaped later icons. The B.zero1 ring of 1999, designed to mark the new millennium, carries a Tubogas-style coil in its band, and the Serpenti snake watches were only possible because of Tubogas bodies. Bulgari's archive team has staged exhibitions in Rome and Milan where visitors can handle the pieces.

In a market often measured by carats, the vintage Tubogas necklace is valued mostly for gold, design and hours of hand coiling, and the recent results show collectors paying well beyond estimates for the strongest examples.

The numbers

Metal

18-karat gold, usually yellow; some bicolor or with steel

Construction

Hollow coiled band, no solder, core removed

Typical size

About 13 inches inner circumference for collars

Typical weight

About 200 g for triple-row collars (199.70 g in one 2023 sale)

Era

Chiefly 1970s to 1990s

Production

Serial production; no published numbers

Timeline

1. 1884

   Sotirios Voulgaris opens his own shop in Rome under the name Bulgari.

2. 1932

   Constantino and Giorgio Bulgari take over the business after their father's death.

3. 1940s

   With platinum requisitioned for the war, Bulgari makes its first plain gold Tubogas jewels, by its archive director's account.

4. 1948

   The first Serpenti, a gold Tubogas bracelet-watch, is made.

5. 1970

   Gianni Bulgari says people now want jewelry they wear often, not just for great occasions.

6. 1970s

   Bulgari revives the Tubogas technique and makes it a trademark, according to the house's official history.

7. 1982

   Bulgari makes a steel-and-gold Tubogas choker and bracelet (dated 1982 to 1984 in its archive).

8. 1999

   The B.zero1 ring launches with a Tubogas-inspired coil.

9. Apr 20, 2023

   A triple-row 18-karat gold Tubogas necklace sells at a U.S. auction for $35,000.

10. Mar 21, 2024

    An emerald and gold Tubogas necklace sells online for $189,000.

11. Dec 4, 2024

    A triple-row flattened Tubogas necklace sells at a U.S. auction for $37,800.

12. May 2025

    Bulgari's archive director speaks on Tubogas at a gem fair in Geneva.

The world in 1970

• Apr 13, 1970

  An oxygen tank explodes aboard Apollo 13; the crew splashes down safely four days later.

• Aug 15, 1971

  President Richard Nixon suspends the convertibility of the U.S. dollar to gold.

• Oct 1973

  Arab oil producers announce an oil embargo after the Yom Kippur War.

• Mar 1974

  The oil embargo is lifted.

• Aug 9, 1974

  Richard Nixon resigns; Gerald Ford becomes president.

Price record

A realized auction price is what a buyer actually paid on the date shown, including the buyer's premium where the sale reported it. It is the strongest kind of reference price, and it is a record of one sale of one object on one day, not a promise of what the next example will bring.

By reference price, Bulgari Tubogas Necklace (vintage 18k gold) is number 47 of 100 in the jewelry entries of the FLOAT 100. 44 of those 100 rest on a realized sale; the rest carry an asking price or a guide value, and each page says which. Rank within the FLOAT 100 itself (68 here) is editorial: how much an object defines its field, not price alone.

Did you know

• Tubogas is named for the gas pipe, tube de gaz in French.
• The coils are formed around a copper or wood core that is pulled out once the band is made.
• A real Tubogas springs in the hand; a fake feels rigid.
• Bulgari's Monete pieces set genuine ancient Greek and Roman coins in Tubogas mounts.
• Bulgari fused aeronautical steel with gold in some 1970s and 1980s Tubogas pieces.
• Without Tubogas, the original Serpenti snake watch would not have been possible.