The results of this analysis, as well as previously unseen archive material about the gem’s history and theft, form part of the exhibition, according to the museum.

Naturally occurring pink diamonds are exceptionally rare and often sell for tens of millions of dollars. The highest price ever fetched for one at auction was $71.2m (£53.6m) in 2017, according to Sotheby’s.

The exact origins of the Grand Condé remain a mystery.

It was first mentioned in 1740 in an inventory of Louis Henri de Bourbon, Prince of Condé, drawn up following his death, the Château de Chantilly said.

It then became part of the collection of Queen Marie-Amélie of Bourbon-Sicily, the wife of French King Louis Philippe I, and then her son, Prince Henri of Orléans, the Duke of Aumale.

He bequeathed it to the Institut de France, which now owns the Château de Chantilly, 50km (31 miles) north of Paris, along with thousands of artworks and manuscripts which became the Musée Condé collection.

(BBC)

The court found the four had been instructed by Li and Zhi to add toxic and harmful ingredients to food served to children and staff.

Food samples were later found to contain lead 2,000 times in excess of China’s national safety limit.

The investigation into the poisoning began after 235 children from Heshi Peixin nursery had to be treated for lead poisoning after eating steamed red date cakes and sausage corn buns.

Investigators found that the red date cake and the corn sausage rolls had lead levels of 1052mg/kg and 1340mg/kg respectively, both of which far exceed the national food safety standard limit of 0.5mg/kg.

Lead poisoning is “particularly harmful to young children” and can “severely damage the brain and central nervous system”, according to the World Health Organization.

Officials later found that dozens of provincial officials and hospital staff attempted to cover up the incident by tampering with blood tests and accepting bribes from a nursery investor.

China has since published a set of national guidelines for the provision of meals on campuses. Among the measures is the requirement for every new batch of food to be tested, and for flour, rice and cooking oil to be purchased from centralised procurement points only.

Earlier, the Houthis denied that they had attacked Saudi Arabia on Thursday, after the coalition said its forces had intercepted a cruise missile in the Medina region, home to one of Islam’s holiest shrines.

The Houthis have been launching missiles and drones at airports, oil and gas facilities, and military bases in Saudi Arabia in retaliation for the strikes on the territory that they control in western Yemen, including the capital Sanaa.

On Saturday, a Houthi missile strike killed 13 people at Riyadh’s international airport, which was the deadliest attack in Saudi Arabia in more than a decade.

Saudi Arabia’s deputy foreign minister accused Iran of encouraging the Houthis to escalate their conflict with the kingdom.

“Iran continues to arm, train and support the Houthi militia in violation of UN Security Council resolutions,” Rayed Krimly told reporters, according to AFP news agency.

“We think that the escalation by the Houthis at this latest stage of the conflict is encouraged by Iran,” he added.

There was no immediate response from Iran’s government. However, it has previously denied supplying weapons to the Houthis and said it only supports them politically.

Iran’s foreign minister has also said it is ready to provide “any assistance necessary to facilitate the start of talks” between Saudi Arabia and the Houthis.