Sarah Ferguson received an extravagant engagement ring from her ex-husband Prince Andrew.

The Duke of York proposed to the Duchess of York with an expensive jewel. Prince Andrew gave Ferguson the Burmese ruby engagement ring that cost $33,000 back in 1986.

"We came to the mutual conclusion that red was probably the best color for Sarah. That's how we came to the choice of the ruby. The extra bits around the outside, we wanted something that was slightly unconventional," Prince Andrew said during their engagement interview (via Good Housekeeping).

Ferguson's engagement ring is not too far behind compared to Princess Diana's engagement ring that cost $37,000 in 1981. The Duchess of York's sparkler featured a big ruby surrounded by 10 diamonds forming a flower pattern on a yellow gold band.

Ferguson described the ring Prince Andrew gave her as "stunning" and "red." She was still seen wearing it after their divorce. However, it remains unknown if she still has the ring. If Ferguson was granted the same rights as Princess Diana, she could keep her own jewels.

Princess Eugenie's engagement ring is similar to her mom. It features a pink padparadscha sapphire that is surrounded by diamonds.

"Like her mother, the Duchess of York and indeed Princess Diana, Eugenie’s ring has a center oval precious gemstone and this one certainly has not disappointed," Deborah Papas, a gemologist from Prestige Pawnbrokers, told the Sun. "It is a padparadscha sapphire surrounded by 10 brilliant cut diamonds and two pear cut diamonds to give an edge to the standard classic cluster."

According to a gem expert, Princess Eugenie's engagement ring costs about $140,000. The cost reportedly doubles Meghan Markle's three-diamond ring that is estimated to worth $70,000.

However, another gemologist thinks that the Duchess of Sussex's ring from Prince Harry is more costly. According to the expert, Markle's engagement ring could cost $174, 218.

"From seeing the pictures, I would estimate that the centre diamond is a slightly elongated cushion cut diamond, approximately 3.00 - 4.00 carats. The side diamonds are more than likely oval or round cut diamonds about 0.75 carats each," the expert explained. "We would estimate that the value of the centre stone would be around £70,000 - £115,000 ($99,553 - $163,552), while the side stones would have an intrinsic value of around £3,750 ($5,333) each."

Sarah Ferguson
What's the story behind Prince Andrew's engagement ring to Sarah Ferguson? Pictured: Prince Andrew and Ferguson attend the Virgin London Marathon on April 25, 2010 in London. Getty Images/Jeff SpicerGareth Cattermole