Speaking to Express.co.uk, the expert stated all the rings are made from a rare gold found in North Wales and bind the royal women together.
“Welsh gold enjoys a historic link with the British Royal Family – and even binds some members together in a very unique way,” Charlotte stated.
“Today it is among the rarest gold in the world largely because the mine it comes from – the Clogau St David mine in North Wales – is no longer in operation.”
Queen Elizabeth, the Queen Mother, was the first to be given the rare gold ring and it has since been used to create jewels for royals including Princess Anne, Sophie, Countess of Wessex and Kate Middleton.
Charlotte continued: “Members of the British Royal Family have used Welsh gold to create their wedding bands since the tradition was initiated by the Queen Mother when she married the Duke of York in 1923.
“Senior royals have been following her tradition ever since.
Charlotte added: “In November 1981, the British Royal Legion presented the Queen with a 36 gram piece of 21-carat Welsh gold for future royal wedding rings.
“Part of this gold was used to create the ring for Sophie, Countess of Wessex and Camilla, Duchess of Cornwall.
“When William and Kate married, the Queen gave William a nugget of Welsh gold to mark his wedding and this was used to fashion Kate’s wedding ring in 2011.”
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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.