When you weigh it, you weigh it. The proportion of gold is greater than other metals, second only to platinum, and it feels heavy in your hand.

The second check is to check the elasticity. The higher the fineness of gold, the softer it is and the less elastic it is; The lower the color, the harder and more elastic it is.

Listen to the rhyme three times. High-quality gold, thrown on the hard ground, makes a clatter, with sound but no elasticity, while low-quality gold has sound but no rhythm, and its sound is long and sharp and elastic.

Four discrimination, that is, color discrimination, can distinguish the approximate color according to the mouth that is 70% clear, 80% yellow and 90% red.

Five tests, that is, testing with chemical reagents. 45% nitric acid can be used for annotation, because gold is insoluble in a single acid, and gold has not changed after annotation.