8K or 8ct is not a legal standard in Ireland or the UK, but as far
as I know it is in Germany where it is also stamped 333.
The lowest legal standard for gold in Ireland and the UK is
9K/9ct/375 this was to stop the import of gold from Germany,
similarly the minimum standard in the US is 10K/10ct/417 to stop the
import of UK and Irish gold.
In Ireland the accepted standards are 9ct, 10ct, 14ct, 18ct, 20ct
and 22ct, then there are marks for 990/1000 and 999/1000.