Kate Middleton and Princess Eugenie
Pictured: Camilla Parker Bowles, Kate Middleton and Princess Eugenie stand together on the balcony at Buckingham Palace following the Queen's Birthday parade, 'Trooping the Colour,' in central London on June 15, 2013. Getty Images/Carl Court

Jack Brooksbank didn't copy Kate Middleton's engagement ring despite its similarities to the one he gave his fiancée, Princess Eugenie.

The Duchess of Cambridge's ring is consists of a 12-carat oval blue sapphire cut into facets and surrounded by 14 solitaire diamonds. It is made from 18k white gold. On the other hand, Princess Eugenie's has sapphire and diamond stones.

Yahoo! Lifestyle shared several shots of Middleton and Princess Eugenie's engagement rings and both looked the same except for the color of the stones. However, according to royal experts, Brooksbank, didn't copy Middleton's ring.

"Although Princess Eugenie's engagement ring is reminiscent of Kate's with the large center sapphire and diamond surround, it's a very classic design for a royal engagement ring and not likely an intentional similarity," royal commentator Eloise Parker said.

Jamie Samhan, deputy editor at Royal Central also believed that if Brooksbank took an inspiration in designing the band it wouldn't be Middleton's but Sarah Ferguson's.

"When Jack Brooksbank proposed to Princess Eugenie, he created a ring that was very similar to her mother, Sarah Ferguson, Duchess of York's, ring," Samhan explained.

In related news, Princess Eugenie and Brooksbank announced their engagement only months after Prince Harry and Meghan Markle did. So, a number of royal fans compared Markle and Princess Eugenie's rings and there were different opinions as to whose ring costs more.

According to Deborah Papas, a gemologist from Prestige Pawnbrokers, Princess Eugenie's ring is more expensive because it contains padparadscha sapphires, which are among the rarest stones. Based on her estimate, the band amounts to $140,000.

On the other hand, she estimated the Duchess of Sussex's three-diamond ring to cost $70,000 only. However, she added that it's difficult to give a more accurate estimate without examining both rings closely. Another gemologist believes that Markle's ring is more expensive and that it's worth $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."