Kate Middleton joined the Royal Family in 2011 when she married Prince William. Since then, the Duchess has been seen wearing an array of different jewellery pieces including a gorgeous citrine ring.

The expert added: “Natural citrine is quite a rare stone.

“In most cases it’s a heated amethyst which is also part of the quartz family.

“However, you get a lot of stone for your money and so it is great for statement pieces as Kate sports in the images.

“Citrine is what we’d describe as a rich summer colour, although it’s the November birthstone with it’s hues of golden yellow and earthy orange.

“Belonging to a royal, I would estimate this piece to fetch £25,000 at auction if it ever be presented.”

Another ring that the Duchess has been seen wearing in recent years is her ruby ring.

Kate debuted it while on a royal tour of Poland in 2017, it is thought that the Duchess wore it in a sweet nod to the Polish flag.

Speaking to Express.co.uk, Roseanna Croft, founder of Roseanna Croft Jewellery explained that the ruby ring could be worth a fortune.

She said: “The Duchess of Cambridge’s ruby ring I estimate to be worth in the region of £35,000 and is a stunning piece of timeless yet ‘on trend’ jewellery – a step away from the traditional jewels worn by the Royal Family.

“The setting is elegant and really helps the stone to stand proud in the ring with a simple diamond set band accentuating the ruby even more.”