Marcasite \Mar"ca*site\, n. [F. marcassite; cf. It. marcassita, Sp. marquesita, Pg. marquezita; all fr. Ar. marqash[=i]tha.]

(Min.) A sulphide of iron resembling pyrite or common iron pyrites in composition, but differing in form; white iron pyrites.

Golden marcasite, tin. [Obs.]

Source: Webster's Revised Unabridged Dictionary (1913)