What is a sulphide of iron resembling pyrite or common iron pyrites in composition, but differing in form; white iron pyrites. Golden marcasite, tin. [Obs.] called?

marcasite — A sulphide of iron resembling pyrite or common iron pyrites in composition, but differing in form; white iron pyrites. Golden marcasite, tin. [Obs.]. (Webster's 1913.)

Sources