This is an easy test for any bar that comes from an accredited mint like Perth, Credit Suisse or RMC. The exact weight is stamped into the bar and should weigh EXACTLY that. There are criminal offenses for misrepresenting the weight on a gold bar so if it weighs anything else, you've found a fake. Make sure your scale is balanced before running this test. It is also best to follow this test with a density test to find if the precious metal is throughout the bar or coin.