Such doubling, is rare on UK coins. Very weak, usually raised shadows or faint hints at duplicate detail around design elements (mostly letters and digits) that tend to extend towards the rim of the coin is caused by die fatigue. This happens when dies are used well beyond their normal working life each coin they have struck has taken its toll on the surface of the die and the repeated metal flow into the incuse die slowly wears out its detail.
Often coins struck with worn dies can have letters and digits that appear fatter and less sharp. A much scarcer and much more pronounced form of doubled detail is caused when a coin is struck from a die that has been engraved with doubled detail in the first place. Doubled die coins are caused by a problem in what is known as the hubbing process, which is an earlier stage of coin production where master dies are created from a relief (raised) impression of how the coin side should look. The hubbing process that imparts the incuse (negative) detail on the master dies doesnt happen once per master die and it is these multiple passes that can, if there is a slight slippage or movement, result in a master die with doubled features.The item "DOUBLE DIE STRUCK ROYAL MINT ERROR 2018 ONE £1 POUND COIN UNC CONDITION" is in sale since Saturday, December 14, 2019. This item is in the category "Coins\Coins\British\Decimal Coinage (c.
The seller is "marlybob1" and is located in Leeds. This item can be shipped to United Kingdom.