The ring worn may have a personal and sentimental meaning, according to CEO of Le Vian Eddie LeVian.
He told Express.co.uk: “This beautiful, delicate ring is understated in style, but the very personal message hidden within it from a future King makes it an enormously romantic royal jewel.
“William gifted Kate this Victorian rose gold band encrusted with pearls and garnets while they were still at St Andrews University where they met as students.
“It’s no surprise Kate was seen wearing it at her graduation.
“It was a milestone marking her own achievements but also a day which put her on the threshold of a new chapter in her life together with William beyond university.”
While in the Royal Family, Kate has worn various eye-catching and sentimental pieces of jewellery.
She was famously given the sapphire and diamond engagement ring which once belonged to Princess Diana.
Prince William also gifted his wife with a diamond eternity ring following the birth of their first child, Prince George, seven.
“Garnets are the birthstone for January, when Kate was born, and were named by the ancient Greeks for their colour resembling pomegranate seeds.”
Not only did the ring contain the couple’s birthstones, the significance of the jewel chosen could have hinted to their royal future together.
“Garnets signify protection and are thought to promote confidence and mental clarity,” the expert concluded.
“Even though Kate graduated in 2005, and the couple married much later in 2011, this ring goes to prove that William was smitten with Kate even in those early days.”
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The royal line of succession – who outranks who?
The line of succession to the British throne dictates the order in which each member of the Royal Family would ascend to the throne.
It is also seen as a ranking of importance with the head of the line, the Queen, taking the place of ruler.
Older children come before younger children. Traditionally boys came before girls, but this law was changed on 26 March 2015 before the birth of Prince William’s first child.
Incredibly, Catholics are still excluded from the line of succession, as are children born outside of wedlock.
The royals, who usually stick to a strict protocol when appearing in public, often arrive at events in ascending order of importance, with the most important royal arriving last.
Prince Charles, 72, is currently first-in-line to the British throne, followed by Prince William, 38, his oldest son.
Then comes Prince William’s children, George, seven, Charlotte, five, and Louis, two, and they are followed by Prince Harry, 36. Prince Harry is succeeded by his son Archie Harrison, born in May 2019.