An ounce is a unit of weight and a troy ounce is the unit of weight that is commonly used to measure gold. A troy ounce is equal to 31.1034768 grams. In terms of size, an ounce of gold is relatively small, as gold is a dense metal. An ounce of gold can be made up of a variety of forms from small flakes, to nuggets, to coins, or bars. A solid ounce of cold is the size of a die or a sugar cube. A gold coin, such as a U.S. gold eagle, that weighs an ounce is around the size of a U.S. quarter. A gold bar that weighs an ounce can be the size of a credit card. Note: It’s important to keep in mind that the size of an ounce of gold can vary depending on the form of the gold, as well as the purity of the gold. For example, a gold nugget that weighs an ounce would be larger than an ounce of gold in the form of flakes or dust. Additionally, the size of an ounce of gold can also be affected by the alloy it’s mixed with, as gold alloys are less dense than pure gold and will be larger in volume for the same weight.