Queen Camilla is paying homage to her late mother-in-law Queen Elizabeth II at her and King Charles III's coronation.

When she was officially crowned Queen during the May 6 event, Camilla sported an altered crown that was originally made for Charles' great-grandmother Queen Mary, who wore it to her and King George V's coronation in 1911. In addition to being the first Queen Consort in more than three centuries to re-use a crown, the piece now honors Elizabeth—who died in September—by including the Cullinan III, IV and V diamonds from the late monarch's personal jewelry collection among the 2,200 diamonds that adorn the silver crown.

"The choice of Queen Mary's Crown by Her Majesty is the first time in recent history that an existing crown will be used for the Coronation of a Consort instead of a new commission being made," Buckingham Palace said in a statement in February, "in the interests of sustainability and efficiency."

The last time a Queen Consort donned a previously used crown for a coronation was in the 18th century, when Queen Caroline, consort of King George II, wore Mary of Modena's crown, the Palace said.

It was also noted that the Cullinan diamonds have been inserted into the crown before—Cullinan III and IV were set temporarily for the 1911 Coronation. As for the Cullinan V, that was included in the crown when Queen Mary wore the piece again, this time as a regal circlet, for the 1937 coronation of her son and Elizabeth's father, King George VI.

Also for Charles and Camilla's coronation, the statement noted that four of the crown's eight detachable arches have been removed "to create a different impression to when the crown was worn by Queen Mary at the 1911 coronation."

Check out more facts about the crown jewels below:

Last used for Queen Elizabeth II in 1953, this crown will be placed on King Charles III's head at the moment of his coronation.

Made for Charles II in 1661, St. Edward's Crown replaced its medieval predecessor that was melted down in 1649. It's made of solid gold and contains rubies, amethysts, sapphires, garnet, topazes and tourmalines. Worth a reported £2.5million, royal correspondent Sharon Carpenter revealed to E! News that the piece weighs five pounds. 

While he was just 4 years old when his mother was crowned with the same diadem, Carpenter said it was "a significant moment" in Charles' life. "It really stuck with him."

Crafted for the coronation of King George VI in 1937, this crown replaced the one that was made for Queen Victoria in 1838. Made of gold and containing 2,868 diamonds, 17 sapphires, 11 emeralds, 269 pearls, and four rubies, this piece contains some of the most famous jewels in the collection: The Black Prince's Ruby, the Stuart Sapphire, and the Cullinan II diamond.

The Imperial State Crown is worn by the monarch as he departs Westminster Abbey after the coronation and is also used on other State occasions because it is a lot "lighter" than St. Edward's, Carpenter explained. "It's more along the lines of three pounds." 

Made in the 12th century, the Coronation Spoon is one of the oldest objects in the Crown Jewels and is used to anoint the sovereign with holy oil.

Used at every coronation since Charles II was crowned in 1661, the 530.2-carat Cullinan I—which is the biggest part of the largest uncut diamond ever found at 3,106 carats—was added to the Sceptre in 1910 for George V.

During the ceremony, King Charles will be presented with objects representing their powers and responsibilities, which is called the investiture. Made in 1661 and mounted with clusters of emeralds, rubies and sapphires, the Orb is a golden globe surmounted by a rose-cut diamond-encrusted cross to remind that the monarch's power is derived from God.

In addition to the Coronation Spoon, the Sceptre and the Imperial State Crown, the Orb was last seen on top of Queen Elizabeth II's casket, Carpenter noted. "People are going to be thinking about Queen Elizabeth because the last time the royals gathered together in this kind of way was to say goodbye to Queen Elizabeth at her funeral Westminster Abbey," the royal expert explained. "She's certainly going to be on people's minds and I'm sure we are going to see various other nods to the late queen in various different ways."

Also referred to as the Stone of Destiny, this historic piece has been moved from Scotland to England for Charles' coronation. Weighing 336 pounds and made of sandstone, the Stone of Scone was used to anoint Scottish kings until Edward I seized it more than 700 years ago. It was returned to its native country in 1996 and, after Charles is crowned sitting in it, it will be taken back to Edinburgh.