1. Different material properties: Copper alloy is an alloy composed of two or more metals such as copper, zinc, nickel and lead. Gold is a chemical element with the chemical symbol of Au, which is a natural precious metal.

2. Different uses: Copper alloys are mainly used to manufacture various mechanical parts, electrical devices, ships and automobile parts. Gold is mainly used as jewelry and currency reserve, and also widely used in circuit boards and other high-tech products.

3. Different colors: the color of copper alloy is brown or artificial gold, while gold looks shiny and pure yellow.