Counterfeit ? Coin

Normal sized circulating coin

Coin, round, with a four-sided hole at the centre, a rim around the outer edge and a centre hole. The obverse has four characters, and the reverse has two characters. Xianfeng tongbao (top-bottom-right-left) in formal style Chinese characters on obverse; boo yun left-right (mintmark) in Manchu on reverse. Character kung (work)? top, crescent bottom on reverse; obverse characters written poorly; rims not filed smooth; surfaces very rough.