Method 1: Look at the color
The higher the purity of gold after smelting, the brighter and darker the color will be.
Generally in the gold content is higher than 95%, in order to reflect the rich gold of gold, rich and bright.
90%-95% purity of gold, the color will be a little red light yellow, brightness is also reduced.
Gold of 80%-85% purity will have a greenish-yellow color in the light yellow
65%-70% purity gold will also have a distinct white light in the greenish-yellow color
For gold of 50-60% purity, only a light yellow color.
If 50% purity is not even there, the overall whitish color presents white.
Method 2: Bite it
Tooth bite gold is actually testing the hardness of gold. This method can filter some gold that is not high purity. Pure gold has low hardness and will leave teeth marks if you bite it with your teeth. So, when identifying pure gold, you can try its hardness, it is impossible to be pure gold if the hardness is too high. (Except for 3D hard gold) This simple and effective method is not generally recommended because it may cause damage to the teeth. In addition, because lead is softer than gold, so gold-plated lead can also leave bite marks on it, causing identification errors.
1、First of all, you have to bite the goldware with proper force.
2, see if there are bite marks on the goldware. Theoretically, real gold will leave bite marks after being bitten, the deeper the bite marks, the higher the purity of gold.
Method 3: Listen to the sound rhyme
Full gold, pure gold jewelry purity is very high, really calm, jewelry landing or collision with each other sound will be low muffled and calm, is the "bar" sound, and landing that does not move; and poor color, low purity or even fake gold landing or bumping each other, will be issued "when when "The metal sound, sometimes also jumping sound, will also jump after landing. But don't knock hard, be careful of deformation.
Method 4: Density test
1, weighing. If you do not have their own scales, you can ask the jewelry on to help you weigh, usually free of charge. The weight should be accurate to grams.
2, in a small bottle filled with water. The vial wall if there is a millimeter scale is best, which will help you more convenient to complete the test. The amount of water does not matter, as long as the water does not overflow after the gold is put in, so do not fill it to the brim. Before and after putting in the goldware, take careful note of the water level height.
3、Put the goldware into the measuring bottle. Record the change in water level before and after, then calculate the increase in water volume to the milliliter.
4、Calculate the density with the following formula. Goldware density = total weight of the goldware / volume of water increase. If the density is close to 19 g/ml, it is real gold, or a metal with a density close to gold. According to the formula to calculate the density, this result on whether the density is close to the real gold will be able to confirm the true or false.
Note that the density of gold varies by purity.
14K gold has a density equivalent to 12.9 to 14.6 g/ml.
Yellow 18K gold has a density equivalent to 15.2 to 15.9 g/mL.
White 18K gold has a density equivalent to 14.7 to 16.9 g/mL
22K gold density equivalent to 17.7 - 17 to 8 g/mL.
Method 5: Spectral analysis
In order to strictly test the purity of gold jewelry also have to find professional institutions through the X-ray spectral analysis instrument to test the sample, can be non-destructive analysis of gold and other impurities in the sample content, the general accuracy can reach 99.9%.