State crown
A State Crown was the working crown worn by a monarch on state occasions such as State Openings of Parliament, as opposed to the coronation crown with which they would be formally crowned. Some state crowns might however be used during parts of the parts of the coronation ceremony. In isolated cases, individual monarchs sometimes chose to use their state crown instead of the official coronation crown for the crowning, but those cases were exceptions rather than the norm.
Some states where there was no ceremonial coronation only had state crowns.
The term state crown was particularly used in the Kingdom of England and its successor Kingdom of Great Britain to describe the crowns of Kings Charles II and George I that were worn on occasions such as the State Opening of Parliament. While the crown of Charles no longer exists, the jewel-less frame of the State Crown of George I is still kept among the British Crown Jewels. Unless the state crown of King Charles, the state crown of King George was also used to crown him with, in preference to the heavier and older St. Edward's Crown.
Because they were constantly in use, in contrast to a coronation crown which was usually only worn once during each reign, state crowns were constantly replaced due to wear and tear.
When, because of its age and fragility, the State Crown of George I was replaced in 1838, the new replacement crown was instead called the Imperial State Crown, as was its replacement in 1937.