Precious metals, including gold are measured in Troy Ounces. There are 31.103 grams in a Troy Ounce of gold.
Note: wrong answer from Google.
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The Troy Ounce is still a standard measure in the gold industry, even though many of the measurements that were used at the start of the metric system are no longer accurate. You can assume the Troy Ounce is being used when you hear or read about ounces and gold.
The Troy Ounce serves as a common measurement for anyone who deals with gold, whether it is in the form of purchasing or manufacturing. The Troy Ounce forms part of the Troy Weights, a system that measures precious metals. A Troy Ounce is made up of 28,35 grams. Troy Ounces are made up of 31.1034807 g. There isn’t a huge difference in the overall weight of these two types of Ounces. However, the extra 2 or 3 gram of gold can make a big difference when it comes to the final size. When comparing a piece like a ring that weighs a Troy Ounce to a standard Ounce, the Troy Ounce ring will be slightly larger or thicker.