Check the official symbol of gold. Generally 999 or 990, or 10K, 18K, 22K, 24K. Anything below 10K is not considered, because the gold content is too low.

Second, the bromine chemical test

Shake the gold products in the alcohol solution for a while, then soak a piece of filter paper in the alcohol solution and drop 4 drops of bromine -A reagent on the filter paper. If the filter paper turns white, then the gold product is real gold.

Three, ceramic scratch test method

Use unglazed ceramics and scrape gold with ceramics. If it is a black scratch, it means it is not gold.

Fourth, hardness test

The purer the gold, the softer the hardness, and the gold with sufficient purity can generally be traced with nails; The smaller the purity, the harder the texture, and the harder it is to paddle.

Fifth, look at the color.

The fineness is the purity. The higher the fineness of gold, the darker the color. People often use "seven greens, eight yellows and nine reds" as a reference for the fineness of gold. The fineness of gold with bluish yellow is 65%~70%, that of light yellow is 80%~85%, and that of deep red is above 95%.

Extended data:

Physical properties of gold

1, color:

The steam released when gold melts is green; Its gold powder is usually brown when it is melted; If it is cast into thin slices, it can transmit green light.

2. Extensibility:

Extremely powerful. 1 oz gold can be stretched to 50 miles long, and its ductility makes it easy to cast, making it a good choice for making jewelry. Of all metals, gold has the greatest pulling force.

3. Extensibility:

Second to none. It will cause extremely thin gold sheets to roll up easily. Gold weighing 65,438+0 ounces can be hammered down to 65,438+0 _ 4 million and 65,438+000 square _ area. The ancients hammered it into thin slices and spread it in temples and palaces for decoration.

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