1911 Great Britain Farthing
Blackened At Mint
NGC AU 53 Brown
King Gregory V
Obverse: Head Left
Reverse: Britannia seated right
in 1897, The United Kingdom started blackening Farthings because of
their resemblance to the Gold Half Sovereign. An acid gas, sodium thiosulphat, was used to color the coin, this process lasted until 1917.