Taylor Swift and Kansas City Chiefs star Travis Kelce announced their engagement on Tuesday with a joint Instagram post that read: “Your English teacher and your gym teacher are getting married”. The news delighted Swift fans around the world, and attention quickly turned to the singer’s vintage-inspired engagement ring.

The piece was designed by New York jewellery designer Kindred Lubeck, a representative for the singer confirmed. Swift’s publicist, Tree Paine, described the diamond as an old mine brilliant cut, but offered no further details.

How much does the ring cost?

Although it’s difficult to determine the value from photos alone, estimates suggest Swift’s ring could be worth up to $1 million.

Mehul Pethani of Cara Jewellers in Dubai places the cost between $150,000 and $500,000, depending on clarity, if bought in the UAE. He tells The National he believes the diamond is about 10 carats. Benjamin Khordipour of Estate Diamond Jewelry gives a figure closer to $550,000, telling Brides.com that the ring is “a stunning elongated antique cushion-cut diamond, approximately eight carats, F colour and VS1 clarity”.

Stephanie Gottlieb, a jeweller often chosen by Swift, told Vogue that she estimates the stone at eight to 10 carats, with a value ranging from $400,000 to $800,000. Meanwhile, Daniela Tarantino, vice president of merchandising at James Allen and Blue Nile, suggests to Glamour that the diamond could weigh between 10 and 15 carats in total, set on a yellow gold band, and likely costs between $750,000 and $1 million.

What is an old mine diamond cut?

An old mine cut is an antique diamond style that was popular from the 18th century through the late 1800s, long before the modern round brilliant became the standard. Recognisable for its cushion-like shape with rounded corners, the cut is defined by a larger culet (the bottom facet of the diamond), a smaller table (the top facet) and a more rectangular or squarish outline that gives it a softer, more romantic appearance.

“Old mine cut diamonds are prized for their unique, vintage charm and historical significance. They’re often sought after by collectors and those drawn to antique or vintage jewellery pieces,” says Pethani.

Where to buy the ring for cheaper

Sterling Forever is offering a dupe – a six-carat CZ sterling silver elongated cushion cocktail ring, available in 14K gold-plated silver or sterling silver, for $129. It’s currently on pre-order, with shipping set to begin on October 6.