The eye-watering price tag on Taylor Swift's one-of-a-kind engagement ring

Taylor Swift is engaged, and her ring is very her.

Australian diamond expert and jeweller Nick Ireland estimates the 10-carat ring given to the singer by NFL star Travis Kelce is worth close to $US1 million ($1.5 million), with an 18K white gold custom-engraved band worth another couple of thousand dollars.

Ireland tells 9honey the elongated, old mine cushion cut design is reminiscent of the engagement rings jewellers used to cut in the early 1700s through to the late 1800s.

READ MORE: Taylor Swift and Travis Kelce announce their engagement

"They didn't have machines cutting diamonds, and so they were cut by hand, and therefore they were never symmetrical," he says.

"So each diamond was very unique, they were never the same.

"Nowadays, there are some polishing houses that actually specialise in cutting old mine diamonds, so they've got the aid of the machine.

READ MORE: Travis Kelce's dad lets slip details on Taylor Swift proposal

"Whilst you can have an old mine cut in a modern way now, it's still cut exactly the same, except they use the machine, so therefore it is perfectly symmetrical."

"They actually sparkle a lot more than they used to back in the day."

Ireland said the ring appears to be hand-cut, giving it that unique, one-of-a-kind shape.

READ MORE: Bruce Willis' wife gives sad update on star amid dementia battle

"It's obviously had quite a bit of work on the ring because it's been hand-engraved ... somebody has taken the time to really put a beautiful design on the band itself," he said.

"You can actually see the bearing that the diamond is sitting on. There's a gold edge, it's almost like a basket that it's sitting in ... but it's got but it's got claws that actually hold the diamond in."

The ring was designed by Kindred Lubeck, the Associated Press reported.

Lubeck is based in New York and runs Artifex Fine Jewellery.

She specialises in hand engraving, and she also collects vintage jewellery, her website reads.

Old mine cushion-cut diamonds have that square shape but with soft, rounded edges.

Ireland often replicates celebrity rings for clients, which he says is a very popular request.

READ MORE: Meghan reminisces about starting out on Deal or No Deal

The Brisbane-based diamond expert says the ring would be easy to replicate with a 5-carat lab-grown diamond, which would cost about $10,000.

FOLLOW US ON WHATSAPP HERE: Stay across all the latest in celebrity, lifestyle and opinion via our WhatsApp channel. No comments, no algorithm and nobody can see your private details.