1973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。深打，虽然偏离中心且仅有部分齿边，但保有巧克力色诱人表面，更闪烁蓝紫色迷人光泽。HONG KONG. Mint Error (Wrong Planchet) 50 Cents, 1973. PCGS MS-63 BN Gold Shield。KM-34; Mars-C37. Error coin struck on 3.6 gms copper planchet instead of the normal copper-nickel. Sharply struck, although off-center and with partial edge reeding, and attractive with chocolate patina and a lovely blue to purple sheen。
