👑 What crown will Camilla be crowned with? Queen Mary's crown
💰 How much is the crown worth? Estimated at £400m
⚖️ How much does the crown weigh? Approximately 590g

Camilla, Queen Consort is set to wear Queen Mary’s Crown when she is crowned Queen Camilla alongside her husband King Charles III at the coronation on 6 May.

It is the first time in almost three centuries that an existing crown will be used for the coronation of a consort, instead of a new crown being commissioned.

Camilla is said to have made the decision to wear Queen Mary’s Crown over a new one in the interest of “sustainability and efficiency”.

In February, Queen Mary’s Crown was removed from the Tower of London, where it is part of the permanent collection of Crown jewels on display, for minor adjustments and modification work ahead of the ceremony in keeping with tradition that crown jewels are adapted uniquely to suit each occasion and wearer.

The changes will reportedly include being reset with the Cullinan III, IV and V diamonds in tribute to the late Queen Elizabeth II.

What is the history of the Queen Mary's Crown?

The art deco-inspired crown was originally created by Crown Jewellers Garrard & Co for Mary of Teck, King George V's consort, for his coronation in 1911.

The design was inspired by Queen Alexandra’s Crown of 1902. Like Queen Alexandra’s Crown, it can be worn without the arches in the form of a circlet, which Queen Mary wore for the coronation of her son, King George VI, in 1937.

This is the first time a queen consort’s crown has been re-used since the 18th century, when Queen Caroline, consort of George II, wore Mary of Modena’s crown.

What are the jewels in the Queen Mary's Crown?

It is laden with 2,800 diamonds set into its platinum frame. The band comprises alternating clusters of diamonds forming crosses and rectangles, bordered by single rows of brilliant-cut diamonds.

The crown also features large diamonds, including one given to Queen Victoria in 1856 by the Sultan of Turkey.

Queen Mary’s Crown is undergoing “minor changes and additions” by the Crown jeweller to add jewels that are “unique to the occasion and reflect the consort’s individual style”, said the palace.

These include a subtle tribute to the late Queen Elizabeth, by including gems from her personal collection: the Cullinan III, IV and V diamonds. Other changes that will be made to Queen Mary’s Crown by the Crown jeweller include removing four of the crown’s eight detachable arches to create “a different impression”.

The Cullinan diamonds are some of the rarest and most expensive diamonds in the world, and were part of the late Queen’s personal jewellery collection, and often worn by her as brooches.

The Cullinan diamonds have been set into Queen Mary’s Crown on previous occasions. Cullinan III and IV were set temporarily in the crown for the 1911 coronation, and the Cullinan V was inserted when the crown was worn as a regal circlet at King George VI’s coronation in 1937.

The crown’s new adjustments also reportedly mean not featuring the controversial Koh-i-Noor diamond or its replica.

Read more: Imperial State crown: How much is it worth and will King Charles wear it?

Why is the Koh-i-Noor diamond so controversial?

Meaning “Mountain of Light” in Persian, the infamous Koh-i-Noor (sometimes Koh-i-Nûr) diamond was originally set in a cross at the front of Queen Mary’s crown for her coronation in 1911, but it was replaced by a replica when the original diamond was moved to the Queen Mother’s crown ahead of her and King George VI’s coronation in 1937.

Although it is one of the largest cut diamonds in the world at 105.6 carats, its infamous history outweighs the Koh-i-Noor’s size and cut.

Whilst there are varying accounts of its origin, most historians agree that it changed hands several times before being signed over to the East India Company in 1849 – which had conquered much of the Indian subcontinent – during British colonial rule by a defeated five-year-old king, Duleep Singh.

For many, the Koh-i-Noor diamond represents the humiliation of colonial rule in India to this day, and its acquisition was so controversial, it has been referred to as "more of a diplomatic grenade than a jewel".

Prince Albert had it recut in the 1850s to make it shine brighter, before it was set in a brooch for Queen Victoria, and eventually incorporated into the Crown jewels.

How much is Queen Mary’s Crown worth?

It is extremely difficult to pinpoint the exact value of Queen Mary’s Crown, given its historical prominence, and the regularly changing feature stones, however estimates can be made based on the weight of the gems added to the crown for Camilla’s coronation.

Maxwell Stone, creative director of jewellery specialist Steven Stone, previously estimated the crown to be worth £836m, but that was when it featured the Koh-i-Noor diamond, which is worth £494m alone.

“Taking into account the removal of the Koh-i-Noor diamond and the addition of the three Cullinan diamonds – which boast a total value of £52m – the crown is likely to be worth around £400m,” estimates Stone.

Watch: King Charles III's coronation: The curious case of the Koh-i-Noor diamond