As well as the general wedding gift, it has been reported that the stunning design was commissioned by the Queen, which is not usually the case.
What are her royal tiaras like?
Queen Victoria Regal Circlet tiara – £1million
The unique design had three peaks and is believed to be made from royal jewels.
Eddie LeVian, CEO of jewellery Le Vian, told Express.co.uk: “The tiara Sophie, Countess of Wessex, wore for her wedding day, the day she became a royal was commissioned for her by the Queen and is widely believed to have been made up of four pieces of Queen Victoria’s Regal Circlet.
“If you look closely, the tiara is composed of four anthemion elements – these are sections composed of twisting diamond floral motifs, set on a gold frame.
“Queen Victoria’s Regal Circlet was made with a set of detachable fleur-de-lis, Maltese cross, and anthemion elements that could be swapped out and rearranged.”
The original tiara has an estimated price tag of £1million and Sophie has worn it on several occasions over the years.
However, having the Queen commission the piece could have hinted at their close bond even before Sophie joined the family.
Eddie added: “The tiara Sophie Countess of Wessex wore was a new tiara made up from antique pieces.
She explained: “The ‘Five Aquamarine Tiara’, also coined the ‘Canadian Aquamarine Tiara’ after the Queen wore it on a state visit to Canada in 1970, is a high sitting tiara with floral and ribbon motifs set with diamonds and large aquamarines.
“It appears incredibly delicate given the size of the stones, each perfectly matched sea blue stone is estimated at around 10 carats.
“This tiara is often assumed to be on permanent loan to the Countess from the Queen, and as a royal favourite, it would possible for this tiara to reach £1 million on the open market today.”
Both tiaras she has been spotted in regularly are thought to permantely be in the possession of Sophie.
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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, 71, is currently second-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, 35. Prince Harry is succeeded by his son Archie Harrison, born in May 2019.