The Stuart Sapphire
Stuart Sapphire from the House of Stuart
The Stuart Sapphire from the Scottish House of Stuart is part of the British Crown Jewels. This extraordinary sapphire is currently mounted on the back of the Imperial State Crown.
The Stuart Sapphire was originally set in the crown of King Alexander II of Scotland for his coronation in 1214. It was then claimed by Edward I of England in 1296.
The stone then passed through the hands of King Edward III of England, his brother-in-law King David II of Scotland, and his sister Marjorie Bruce, who later named the sapphire after her son Robert II, the first monarch of the House of Stuart.
Oliver Cromwell then sold the Stuart Sapphire and the rest of the Crown Jewels. Once the monarchy had been restored, it was returned to Charles II of England.
When James II went into exile in France in 1688, it's believed he smuggled the Stuart Sapphire with him. After his death, it was passed to his son James Stuart, who in turn passed it to his son Henry Benedict, Cardinal Duke of York. When he died, it was left to George III.
In 1838, Queen Victoria had the Stuart Sapphire set in the front of the Imperial State Crown, below the Black Prince's Ruby. In 1909, it was moved to the back of the crown to make space for the 317-carat (63 gram) cushion-shaped Cullinan II diamond.
Queen Elizabeth II wore the Imperial State Crown after her coronation and each year during the state opening of parliament.
After her death, the crown was placed on her coffin during the laying-in-state at Westminster Hall and remained there throughout the funeral ceremony. It was removed shortly before the coffin was lowered into the royal vault at St George's Chapel in Windsor Castle. 
The blue gemstone in the Maltese Cross at the top of the Imperial State Crown is the St Edward's Sapphire.
In his book, The Jewel House, Major-General Sir George Younghusband writes;
In the band at the back of the King’s State Crown may be seen a very large sapphire, known as the Stuart sapphire, which has seen many adventures. What its early history was is not known, but at one end is drilled a longitudinal hole evidently made for some attachment so that the stone might be worn as a pendant.
It first came into recognition in the reign of Charles II, who wore it in his crown, but whether he received it from Charles I or acquired it in his wanderings is not quite clear. At his death the sapphire passed to James II, who when he was dethroned and fled to France took it with him.
James II left the sapphire to his son, 161Charles Edward, the Old Pretender, who in his turn left it to his son, Henry Bentinck, known as Cardinal Yorke, by whom it was bequeathed, with other Stuart relics, to George III. George IV and William IV in turn owned it, and then it came to Queen Victoria, who very greatly prized it and had it set in the band of her State Crown, in the front and just below the Black Prince’s ruby. This pride of place the Stuart sapphire resigned in favour of the Star of Africa, a portion of which Edward VII placed in the crown, symbolising the entry of the Union of South Africa into the brotherhood of the British Empire.
The Stuart sapphire is of great size, being about 1-1/2 inches in length by 1 in. in breadth, and is oval in shape. It is without serious flaw and of good colour, though paler than some of the best sapphires to be found in other portions of the regalia. The stone is set in a gold brooch, and can be removed and worn as a personal ornament.
George Younghusband was appointed the post of Keeper of the Jewel House by King George V in 1917. The Jewel House, which houses the British Crown Jewels, is in the Tower of London.
