Penny (Irish decimal coin) Penny (Irish decimal coin) The decimal one penny (1p) () coin was the second smallest denomination of the Irish pound. It was first issued when the Irish currency was decimalised on Decimal Day, 15 February 1971. It was the second of three new designs introduced all in bronze, the others being a half-penny and a two pence coin. All featured ornamental birds designed by Irish artist Gabriel Hayes on the reverse. The coin originally had a diameter of 2.032 centimetres and mass of 3.564 grams consisting of copper, tin and zinc. This was identical to the British decimal penny as
Coins of the pound sterling of the 20p coin has also been amended to incorporate the year, which had been on the reverse of the coin since its introduction in 1982 (giving rise to an unusual issue of a mule version without any date at all). The orientation of both sides of the 50p coin has been rotated through 180 degrees, meaning the bottom of the coin is now a corner rather than a flat edge. The numerals showing the decimal value of each coin, previously present on all coins except £2 and £1, have been removed, leaving the values spelled out in words only.