A) Streak: Gold has a yellow streak. Pyrite has a greenish black streak.

B) Hardness: Gold has a Mohs hardness of 2.5, while pyrite has a Mohs hardness of 6 to 6.5. Gold will not scratch a copper surface (Mohs hardness of 3), but pyrite will easily scratch copper. Gold can be scratched by a sharp piece of copper, but copper will scratch very few other materials.

C) Ductility: Gold is very ductile, and a tiny piece of gold will bend or dent with pressure from a pin or a pointed piece of wood. Tiny pieces of pyrite will break or resist the pressure.

D) Sectility: Small particles of gold can be cut with a sharp pocket knife. Small particles of pyrite cannot be cut.