1. Color: Gold is a unique yellow color, while iron pyrite is a brassy yellow or pale gold color.

2. Luster: Gold has a metallic luster, while iron pyrite has a metallic or dull luster.

3. Weight: Gold is denser than iron pyrite, so a piece of gold will feel heavier than a piece of iron pyrite of the same size.

4. Hardness: Gold is softer than iron pyrite, so gold can be scratched with a fingernail, while iron pyrite cannot.

5. Streak: The streak of gold is gold, while the streak of iron pyrite is black or greenish-black. (To determine an object’s streak, rub the object against a streak plate.)

6. Cleavage: Gold has no cleavage, while iron pyrite can be easily cleaved into small cubes.

7. Magnetic Properties: Iron pyrite is magnetic, while gold is not.

8. Chemical Tests: There are also several chemical tests that can be used to distinguish gold from iron pyrite, such as the nitric acid test and the aqua regia test. (Note: This can permanently alter the object.)

If you are still unsure whether something is gold or iron pyrite, it is best to consult with a professional jeweler or geologist for further testing.