First, measure the weight of a pure gold bar with a balance, then put the gold bar into a measuring cup and pour water to drown it. Then put the detected gold bars into a measuring cup and observe whether the scale of water rises or falls. As long as there is a change, it means that gold bars are not pure gold. But if it is gold jewelry, this method is not applicable, because there is air in gold jewelry.

Extended data:

Common are gold bars, nuggets, ingots, various ornaments, utensils, gold coins, industrial gold wires, sheets and plates. Gold with a fairly high purity after purification is called pure gold, and gold generally refers to pure gold with a purity of over 99.6%.

1. Red gold and pure gold have similar meanings, but the standard of red gold varies with time and place. Gold with a purity of 99.6% sold in the international market is called red gold. Domestic red gold is generally between 99.2% and 99.6%.

2. Non-ferrous gold, also known as "secondary gold" and "tidal gold", refers to gold with low fineness. Due to the different contents of other metals, the purity of these gold is as high as 99% and as low as 30%.

According to the classification of other metals, ripe gold can be divided into solid gold, mixed gold and K gold. Clear gold means that gold is only mixed with silver, regardless of its fineness. Clear gold is more common in gold bars, ingots, nuggets and various utensils and gold ornaments.

3. Mixed color gold means that besides silver, gold also contains other metals such as copper, zinc, lead and iron. According to the different types and quantities of metals, it can be divided into small mixed gold, large mixed gold, bronze mixed gold and lead mixed gold.

4. K gold means that silver and copper are mixed in a certain proportion, and the pure gold calculated according to the formula is 24k. Generally speaking, the more silver in K gold, the bluer the color; If the proportion of copper is large, the color is purple.

References:

Baidu encyclopedia-gold