Are you new to this? A one ounce gold coin contains one ounce of gold. If they are soft pure 24C gold, the coin weighs one ounce. (Troy, of course, we are talking about.)
If they are harder 22C gold, they still contain one ounce of gold, plus copper, silver and other metals to make them harder and more durable. In that cases, the coins weigh about 1.1 ounce, with 1.0 ounces of it being pure gold.
Really, you didn’t know this?