Countermarked Coin for use in Jamaica

A countermarked silver 8 reales coin. The front shows a crowned shield of arms. The front is partially obscured by the countermark, but would have featured crowned hemispheres flanked by crowned pillars. The coin has been countermarked with "GR" in a circle on both sides directly in the centre of the coin. This coin was produced in Peru (with a Lima mint mark), but was countermarked for circulation in Jamaica, at that point a British colony.