1978年香港伍毫错版。铸于3.6克红铜坯饼上,而非正常的镍黄铜合金。光泽亮丽,底板闪现充沛原厂红光。HONG KONG. Mint Error (Wrong Planchet) 50 Cents, 1978. PCGS MS-64 RB Gold Shield。KM-41; Mars-C38. Error coin struck on 3.6 grams copper planchet instead of the normal nickel-brass. Lustrous with abundant mint red in fields。