Fool's gold often forms in a different geological setting. The old miners that were worth their salt could tell the difference without a streak plate. However, I really don't understand what a cation is. On page 143 of Dolgoff, ion is defined as a charged atom. The charge develops when an atom looses or gains an electron.
Cations lose electrons and anions gain electrons.
Because of the opposite charge on cations and anions, they attract to form a bond known as an ionic bond.