Kate Middleton reportedly has the most expensive engagement ring among the partners of Prince Charles and Prince Harry.

According to the Sunday Express, the Duchess of Cambridge’s stunning sapphire ring with diamonds was a family heirloom. It once belonged to Prince William and Prince Harry’s mom, Princess Diana. After Prince Charles gave the ring to Princess Diana in 1981, the jewelry would have cost over $38,000.

But taking into account inflation, the ring would have been priced over $135,000. And since the engagement ring was used to propose to Middleton, its value has increased to over $400,000.

In November, Michael Fried, the CEO of Diamond Pro, told People that Markle’s engagement ring, which was sourced out from Botswana, could be priced at $200,000.

“A three-carat diamond like that should cost around $200,000, though the diamond qualities of us non-royal folk usually go with would allow us to get a similar sized diamond for about $80,000,” he said

Markle’s engagement ring featured a huge diamond from Botswana as its centerpiece. It also included smaller diamonds taken from one of Princess Diana’s jewelries. And as such, it has been dubbed as “priceless.”

“There is no way for me to put value on the whole ring. Having diamonds from the royal collection that Princess Diana wore makes the ring priceless,” Fried said.

Meanwhile, Camilla Parker Bowlesengagement ring came from Queen Elizabeth II’s massive jewelry collection. The huge statement jewelry features an art deco design and a modest gold wedding band.

Grant Mobley, a gemologist and director of Pluczenik, told Express, “I would imagine the approximate five-carat large emerald cut center diamond flanked by six baguettes in art deco pattern and platinum setting would be worth around $225,000.”

If all of the estimates for the three engagement rings are correct, this could only mean that Middleton’s ring is the most expensive one. Markle’s engagement ring, on the other hand, is the cheapest among the three.

Kate Middleton, Meghan Markle
Kate Middleton’s engagement ring is more expensive than Meghan Markle’s engagement ring. Pictured: Middleton, Markle attend Christmas Day Church service at Church of St Mary Magdalene on Dec. 25, 2017 in King's Lynn, England. Getty Images/Chris Jackson