Short answers, pulled from the story.
St Edward's Crown is 22-carat gold, stands 30 cm tall, and weighs 2.23 kg. It is set with 444 precious and fine gemstones, including 345 rose-cut aquamarines, 37 white topazes, 27 tourmalines, 12 rubies, 7 amethysts, and 6 sapphires, among others. Its purple velvet cap is trimmed with ermine.
St Edward's Crown is named after Saint Edward the Confessor, the Anglo-Saxon king canonised in 1161. Edward is thought to have worn the original crown on Easter Day 1065, and the monks at Westminster Abbey, his burial place, claimed he had asked them to use his regalia for all future coronations.
Following the execution of Charles I in 1649, Parliament ordered the regalia to be broken up, the gold and silver melted down, and the jewels sold. The original St Edward's Crown was listed in a parliamentary inventory at a total value of £248 10s 0d. Carew Mildmay, Clerk of the Jewel House, returned the destruction order marked "not obeyed" and was jailed at Fleet Prison.
The current St Edward's Crown was made for the coronation of Charles II in 1661 by the Royal Goldsmith Sir Robert Vyner. A long-held theory that it incorporated gold from the medieval original was overturned by research in 2008, which found that the crown was newly commissioned in 1660 and enhanced with additional gold in 1661.
Only seven monarchs have been crowned with St Edward's Crown since the Restoration: Charles II in 1661, James II in 1685, William III in 1689, George V in 1911, George VI in 1937, Elizabeth II in 1953, and Charles III in 2023. Many monarchs, including Queen Victoria and Edward VII, used lighter alternatives because of the crown's weight.
St Edward's Crown is normally on public display in the Jewel House at the Tower of London. It left the Tower in June 2013 for a service at Westminster Abbey marking the 60th anniversary of Elizabeth II's coronation, the first time it had done so since 1953. It was also removed in December 2022 to be resized for the coronation of Charles III.