Royal gems make 60th anniversary truly diamond celebration for Queen

The major display will reunite for the first time seven of the nine principal stones cut from the Cullinan Diamond.

The gems are set in brooches, a ring and a necklace, many of which have been worn by the Queen throughout her reign, with the remaining two stones forming part of the Crown Jewels.

The exhibition, which will be the focal point of Buckingham Palace’s 2012 summer opening, will include an unprecedented display of some of the Sovereign’s personal jewels.

At the heart of the display are the gems from the Cullinan Diamond, which weighed 3,106 carats in its rough state when discovered at a mine near Pretoria in South Africa in 1905.

At first it was thought to be crystal, as it was three times larger than any other diamond that had been found.

Exhibition curator Caroline de Guitaut said: “Until 26 January 1905 no one had ever seen a diamond of this size.

“So incredible was its discovery that the moment it was found at the Premier mine it was thrown out of the window of the mine manager’s office because it was thought to be a worthless crystal.”

The clerks who had thrown the stone away were eventually persuaded it was a real gem and it was named after the chairman of the mining company, Thomas Cullinan.

In 1909, after it had been cut and polished, the two largest gems were formally presented to Edward VII.

These are the largest colourless and flawless cut diamonds in the world, with the biggest – the Great Star of Africa – set in the Sovereign’s Sceptre and the second gem – the Second Star of Africa – set in the Imperial State Crown. Both are on display at the Tower of London.

Among the items that will go on show at the Palace will be the Girls of Great Britain Tiara which the Queen recently wore at the state banquet for the Turkish president in November.