There were no quarters issued in 1808.
A Double Sovereign is a gold coin of Two Pounds face value. During Queen Victoria's reign, they were only issued in 1887 and 1893 and were minted to a standard 16 grams and 28 mm in diameter.
A Sovereign has a face value of One Pound (GBP). In today's currency, a quarter of a Sovereign would be 25 Pence.
Australia does not produce any Sovereign coins.
There were no 1981 British Half-Sovereign minted.
The Sovereign is a coin, not a value. It does not have a symbol. The value of the Sovereign is One Pound. In the pre-decimal currency, it was also equal to One Pound (or 20 Shillings).
A Sovereign is Sterling coin. In 1880 a Sovereign was worth a Sovereign or One Pound. It's face value has not changed since it was reintroduced into the currency in 1817.
The Sovereign was not reintroduced into the British currency until 1817.
After a break of a few hundred years, the Sovereign was reintroduced into the British currency in 1817. There was no 1802 Sovereign.
About 50 euro.
The Royal Mint did not produce a 1919 Half-Sovereign coin.
The U.S. did not mint any dimes in 1808. Please check your coin again and post a new question with more details to help ID it.