Gold is often mixed with other metals to make it harder and to increase its value. Because of this, it is not always easy to determine whether or not an item is made of gold. One way to test for gold is by using a lighter. When you hold a lighter up to a piece of gold, the flame will reflect off the metal in a certain way. If the item is not made of gold, the flame will be orange. If the item is made of gold, the flame will be yellow.