Taylor Swift's engagement ring reflects current fashion trends and a return to antique elegance, according to Giuliano Ansuini, a fifth generation jewellery store owner in Rome, and an expert in vintage jewels.

“We have lots of vintage items and many antique-cut diamonds. It should be noted that the price of antique cuts is rising,” he said explaining that today some antique cuts are usually more expensive than modern ones.

Swift's ring is a unique piece, according to Ansuini, who estimated its value at around 500,000 euros - that's about $672,000.

The pop star announced her engagement to Travis Kelce on Instagram.

The cut dates to 18th-century candlelight, and was designed by Kindred Lubeck, a representative for the pop star confirmed.

The diamond is an old mine brilliant cut, said Swift’s publicist.

Old mine brilliant cuts are often boxy shaped with rounded corners and soft curved edges.

Swift’s diamond is in a yellow gold bezel setting.

Such diamonds usually have 58 large facets and the style dates to the 18th century.

The bulky nature of the cut was intended to sparkle by candlelight.

“It's a stone that is 4 million years old, and it's not easy to find one that big on the market,” said Ansuini.

Ansuini Jewellery was founded in Rome in 1860.

Giuliano Ansuini took over in 1990 and now runs it with his son Nicola, the sixth generation of the jewellery business.

AP Production by Maria Selene Clemente