The color of gold is golden yellow, which has a metallic texture and is not easy to decompose. Hardness 2-3, pure gold 19.3, melting point1064.4℃; Good ductility, can be pressed into thin foil, and has extremely high heat and thermal conductivity. The resistance of pure gold is 2.4p Pure gold has good chemical resistance and is the best electroplating material.

Brass is an alloy of copper and zinc. Brass composed of copper and zinc is called ordinary brass. If it is a variety of alloys composed of more than two elements, it is called special brass. Brass has strong wear resistance. Brass is usually used to make connecting pipes for indoor and outdoor machines of valves, water pipes, air conditioners and radiators.

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Gold identification adulteration

1. Does gold have white highlights?

Cut the gold bars or jewelry with scissors, and observe the section with a magnifying glass. If you see white bright spots, because gold and iridium can't blend together, it means that gold is doped with iridium.

2. Measure the specific gravity.

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.

Real gold is not afraid of fire.

Put gold bars or gold jewelry on the fire for a period of time and observe its changes. Because iridium will combine with oxygen in the air to produce oxidation reaction, gold bars with insufficient purity will turn gray; And pure gold will appear bright red after being baked by fire. However, this method may have some damage to jewelry.

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