As well as being carried in the sceptre, the Great Star of Africa can be worn as a brooch – a style favoured by the wife of King George V, Queen Mary.

According to consumer intelligence tool Brandwatch, the Great Star of Africa was a big topic of discussion on Twitter on April 21 as the Queen celebrated her 96th birthday.

Much of the discussion online centred on the diamond’s controversial past, as it has been claimed the diamond was stolen and should be returned to South Africa where it was found.

The Great Star of Africa is not the only large diamond that is controversially part of the royal collection. The famous Koh-i-Noor diamond entered the Royal Family’s possession during the reign of Queen Victoria.