What to know about the controversial Crown Jewels to be used in King Charles III's coronation

Camilla, the Queen Consort, will be crowned with an existing crown on Saturday at King Charles III's coronation, but one that has undergone a transformation due, in part, to controversy.

Rather than commission a new crown for the coronation service, as has been customary in royal tradition, Camilla, will wear a modified version of the Queen Mary's Crown during the service at Westminster Abbey on May 6, according to Buckingham Palace.

Among the changes being made to the crown for Camilla, according to Buckingham Palace, include the removal of the replica of the Koh-i-Noor diamond, the original version of which was first set on Queen Mary's Crown in 1911.

The history of the 105-carat Koh-i-Noor diamond is entangled in a centuries-long chain of conquest and controversy. It passed through the hands of Persian generals, Mughal emperors and Iranian warriors before being presented to Queen Victoria by the deputy chairman of the East India Company in the 1840s.

"It is, in some respects, the ultimate blood diamond in South Asian history," Priya Atwal, author and historian at the University of Oxford, told ABC News. "Its origins are rather mysterious and quite legendary, and is this ultimate symbol of the internal political histories of the subcontinent."

It has been reported that controversy surrounding the symbolism of the Koh-i-Noor is likely to have contributed to Camilla's decision to exclude the gem from the crown she wears at the coronation.

"The Koh-i-Noor is too controversial right now to risk the queen consort wearing it," Adrienne Munich, professor emeritus at Stony Brook University and author of the book "Empire of Diamonds," told ABC News. "The diamond has a bloody history, reaching back millennia, if myth and history come together."

Shortly after the death of Queen Elizabeth II last year, "Koh-i-Noor" began trending on social media as users discussed royal regalia and the reminders they bring of colonization.

While the United Kingdom has maintained and retained ownership of the diamond over the years, the diamond's ownership remains a point of international contention. India, Pakistan, Afghanistan and Iran have all called for its restitution from British possession.

According to Buckingham Palace, Camilla's decision to not commission a new crown was made, "in the interests of sustainability and efficiency."

The palace also said in a statement the choice to adorn the crown with new jewels is part of a, "longstanding tradition that the insertion of jewels is unique to the occasion, and reflects the Consort’s individual style."

"Even with commissioning new crowns, none of that is happening in this coronation, and I find that particularly interesting because the language that's been used in the statements in Buckingham Palace is that these jewels and the older crowns are being recycled in the interest of sustainability and efficiency," Atwal said. "But nevertheless, monarchs have been very aware and royal committees have been very aware that diamonds and jewels are inherently symbolic."

On Saturday, when the eyes of the world are on Camilla and Charles, Camilla's crown will instead feature the Cullinan III, IV and V diamonds.

The diamonds' inclusion is a tribute to the late queen, who counted the diamonds as part of her personal jewelry collection, according to Buckingham Palace.

The Cullinan III, IV and V diamonds -- known as the "Lesser stars of Africa" -- are part of a group of stones produced from the Cullinan diamond, which was discovered in 1905 in Pretoria, South Africa.

Known as the famous "Great Star of Africa," the 530-carat Cullinan I, is the largest-cut diamond made from this stone.

It currently sits on the Sovereign's Spector with Cross, which will be handed to Charles along with other regalia during the coronation.

Though the Cullinan diamonds have previously been set on the Queen Mary's Crown, they too are not without controversy.

The Cullinan diamond was purchased by South Africa's Transvaal government prior to being gifted to King Edward VII as a "symbolic gesture" to heal rifts between South Africa and Britain following the Anglo-Boer Wars.

Over the years, there have been calls from leaders in Africa for the repatriation of "The Stars of Africa."

"South Africans are increasingly saying this is again a massive symbol of how so much wealth, so much resource was drained from our country," said Atwal. "If you swap the Koh-i-Noor for the South African diamonds, you're still in very tricky waters, and I think that is the thing that the monarchy is in, is this catch-22 situation."

Following the coronation, the Cullinan diamonds will return to a display at the Tower of London, as part of the Crown Jewels collection.

Beginning on May 26, the Koh-i-Noor diamond will also be on public display, and back on the Queen Mother's Crown, in a new exhibition at the Tower of London.

ABC News' Zoe Magee contributed to this report.