The British Museum has acquired a shimmering 3,000-year-old gold sun pendant heralded as one of the most important bronze age finds of the last century.

The astonishingly well-preserved pendant, or bulla, was discovered by a metal detector enthusiast in Shropshire in 2018.

Neil Wilkin, the museum’s bronze age curator, recalled dropping everything when he first saw it. “I was absolutely flabbergasted, I couldn’t believe my eyes,” he said. “To me it is the most important object from this period, the first age of metal, that has come up in about 100 years.”

The pendant has been purchased for £250,000 using money from the Art Fund and the American Friends of the British Museum.

Wilkin said it could easily pass as a glorious example of art deco jewellery from the 1930s. In reality it was made by someone who was clearly skilled in their craft around 1,000-800BC. “The skill and care with which it has been put together is remarkable,” he said. “It is just exquisite.”

It comes from a period that is often misunderstood, associated with people living in huts or caves. Wilkin said that was understandable. “This is a subject, a period, that hasn’t been taught in school curriculums until very recently … I didn’t learn about it at school.”

The pendant is decorated with semi-circles and geometric motifs, and on one side is a stylised solar design, reflecting the importance of the sun and its path across the sky to bronze age farmers.

That depiction of the sun is seen in famous objects as the Trundholm sun chariot in Copenhagen and a small number of gold pendants found in Ireland, “but we haven’t really seen it on British objects until now,” said Wilkins.

The pendant is decorated with semi-circles and geometric motifs, and on one side is a stylised solar design. Photograph: British Museum

The pendant was found in a landscape that would have been boggy and wet during the bronze age. Curators think it would have been intentionally cast into the water as an offering, much as people today throw coins into fountains.

It was found by a metal detectorist who wants to remain anonymous. All the correct procedures were adhered to in that it was reported to the local finds liaison officer who notified the coroner and brought it to the British Museum under the treasure process.

A coroner found it to be treasure and the independent treasure valuation committee recommended to the culture secretary a valuation of £250,000.

It will probably be known as the Shropshire sun pendant and will go on display from November at Shrewsbury museum and art gallery, near the find site. In 2021 it will come to the British Museum in London and will be displayed near other bronze age treasures such as the Mold gold cape.

The pendant, 3.6cm by 4.7cm, is the second one ever found in Britain. The first was discovered during canal digging in Manchester in 1722 and was assumed by many experts to be Roman, because of its quality. It was last recorded in 1806 before disappearing from sight.

Could it still be out there? “It is possible,” said Wilkin. “To find it would be astonishing but in some ways it wouldn’t surprise me. The weight of it means you wouldn’t necessarily think of melting it down for bullion. I do have a sneaking suspicion it is out there somewhere, just misunderstood or mislabelled.”