Lauren Kiehna says King Charles and Camilla would be keen to avoid additional criticism. Photo / Getty Images
In Britain, it has been used in the crowning of Queens for generations with pomp, ceremony but little noticeable fuss, mounted on successive crowns worn by Queen Alexandra, Queen Mary and Queen Elizabeth.
In parts of the rest of the world, it is a 1000-year-old symbol of Empire and the focus of ongoing upset that now appears to be coming to a head.
The Koh-i-Noor diamond, which has been part of the Crown Jewels for more than 150 years, is at the centre of renewed calls for its return - with India the most diplomatically critical country making a claim to it.
As the new King and Queen Consort plan for a Coronation unlike any other before them, it is the very last thing they will want to take centre stage.
The diamond, which is often said to have been "given" to Britain in 1849, is currently set in the crown worn by Queen Elizabeth, later the Queen Mother, in her own 1937 coronation.
The crown was thought to be a front-runner among the options for Queen Camilla to wear for next year's Coronation, and has been under discussion at the palace for as long as it has been understood she will join the King for the ceremony.
'Sensitive to the issues surrounding today'
One source suggested that the jewel had not, until recently, been treated as "problematic".
But, they said, aides were particularly alert to move with the times.
"The Coronation has deliberately been kept quite unplanned, unlike the Bridges programme [for the late Queen's death] to ensure it can best reflect the climate at the time at which it happens," they said.
"Now is when the planning will begin in earnest, and people at the palace will be acutely aware of and wanting to reflect tradition whilst being sensitive to the issues around today.
"At this stage, it's entirely possible that the Koh-i-Noor will be in or out. Bluntly, people will be wondering whether they really want a row over a diamond right now."
A separate source told the Daily Mail that the King was "acutely sensitive" to the issue, with advisers having "significant nervousness" around using the crown jewel.
William Dalrymple, co-author of a book describing the Koh-i-Noor as "the world's most infamous diamond" said its ownership was "not a small sensitive issue in the eyes of India" but a "massive diplomatic grenade".
Diamond one of biggest signifiers of British victory
Jyoti Atwal, associate professor at Jawaharlal Nehru University, explained the diamond's significance, telling Britain's Daily Telegraph how it travelled around the medieval world as a "prized possession" and in 1851, after British annexation, "went to the United Kingdom via a treaty with an 11-year-old King in Punjab".
"In the colonial discourse it was seen as a gift from India, although it has a chequered history of being owned by different kingdoms across South Asia and West Asia," she said. "It was one of the biggest signifiers of victory for Britain over the subcontinent and since India's independence in 1947, there have been demands of bringing it back.
"It has always been at the centre of political restoration and restoring Indian pride, and doing away with this blot in history."
A resurgence of interest in "bringing it back" was now "very visible" among a new generation on social media, she added.
Saurav Dutt, an author and political commentator born in Kolkata and raised in the UK, said: "Ensuring the Koh-i-Noor remains front and centre in the public eye in this way flies in the face of any attempt by the royal family and political orthodoxies to draw a line under the dispossession, prejudice, plunder and exploitation that imperialism revelled in.
"Such a position is at odds with the modern, egalitarian stance the royals seek to present themselves within a world that seeks to move on from the ugliest chapters of history that they benefited from."
Creation of new crown unlikely
Options for the Queen Consort's coronation crown include using the existing crown worn by Queen Elizabeth - originally thought to be the most cost-effective and simplest option.
It could be resized and modified to replace the Koh-i-Noor, or a different and less contentious crown chosen for the occasion.
Queen Alexandra and Queen Mary both had new crowns made for their coronations, with the precious diamonds later replaced by crystal versions.
Lauren Kiehna, a royal jewellery expert who writes a blog under the name of The Court Jeweller, last week predicted that the creation of a new crown for Queen Camilla was unlikely but called the inclusion of the Koh-i-Noor diamond a "real, serious sticking point".
"I would imagine that Charles and Camilla would be keen to avoid additional criticism when possible, and Charles particularly has always seemed sensitive to the fact that jewels can carry significant symbolism," she wrote.
'Single most valuable object in entire subcontinent'
The diamond, thought to have originated in South India, has previously been claimed by Afghanistan, Iran and Pakistan.
Described by Dalrymple as "arguably the single most valuable object in not just the Punjab but the entire subcontinent", the Koh-i-Noor was signed over to the British East India Company in 1849 along with vast areas of land in the Treaty of Lahore.
It is described by the Royal Collection Trust as being "surrendered" to Queen Victoria "by the Maharaja Duleep Singh in 1849".
At the time, the maharajah of the Punjab was 11 years old.
The jewel was brought back to Britain for presentation to Queen Victoria a year later, and put on display to the public at the Great Exhibition.
Afterwards, it was cut by Garrard & Co and turned into a brooch worn by Victoria.