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There are many identification methods for gold jewelry. The Chinese people have summarized a set of simple methods. The key words are: look at the color, weigh the weight, listen to the rhyme, fold the hardness, grind on the stone, compare the brand, use the acid point, and determine the color. The first four sentences depend on eyesight and feeling; The last four sentences need tools and reagents I. according to the different luster and color of gold, we can generally distinguish pure gold, K gold, real gold and fake gold. That is, the best gold is red yellow, and the fineness is above 95%; The fineness of positive yellow is about 80%; The fineness of cyan and yellow is about 70%; The yellow is slightly gray, and the fineness is about 50%. Therefore, there is a saying "seven green, eight yellow, nine five red, yellow and white with gray and half gold". For jewelry that has been stored for a long time, there is a saying that "copper turns green, silver turns black, and gold never changes color". 2、 Look at the density. The density of gold is 19.32 g / cubic centimeter, which is about twice the weight of silver, lead and tin in the same volume. Available formula: the mass (g) of a certain gold jewelry is equal to the volume (cubic centimeter) of a certain gold jewelry. Calculate the density of the measured gold jewelry. If the density is about 19.32g/cm3, it is pure gold or relatively pure gold. Otherwise, it is non pure gold or gold with color difference (this method is not destructive to jewelry). III. bending hardness gold has the characteristics of ductility and small hardness, and can be pressed into a thin sheet with a thickness of 12.7 microns. When the quality is high, marks can be left with pins or nails. For gold jewelry with more than 97% fineness, wrinkles appear at the bend after two or three times of bending, also known as fish scale lines; About 95% of the gold jewelry of good quality feels hard when it is bent, and the fish scale pattern is not obvious; About 90% of the gold jewelry of good quality is very hard when it is bent, and there is no fish scale pattern; Gold jewelry with more impurities can be broken after two or three times of bending; If it is made of raw gold, the bend is broken, and the section has obvious sand grain shape. When using this method, we should consider the width and thickness of jewelry. The thick and wide jewelry is harder, and the thin and narrow jewelry is softer. IV. when gold jewelry with high elasticity and fineness is knocked or thrown on the hard ground, it will make a dull and low sound of "puta, puta" without rhyme and elasticity. K gold has rhyme, sound and elasticity. The greater the elasticity and the sharper the sound, the longer the sound, the worse the fineness. V. use the touchstone to identify the fineness. Use the gold matching plate (the gold medal with determined fineness) and the tested jewelry to grind on the touchstone, and determine the fineness of the gold jewelry by comparing the colors. This method should be carried out under natural light and fluorescent lamp, not under direct sunlight and incandescent lamp. Vi. grind the identified jewelry and the gold track of the matching brand on the touchstone with acid point, and test the nitric acid on the gold track with glass rod. Because the chemical property of the gold element is stable and does not react with acid, the color remains unchanged. If it is not gold or pure gold, the golden path will disappear or change. The change law is "three fast and three slow", that is, the low quality disappears quickly and the high quality disappears slowly; Mixed gold disappears quickly and clear gold disappears slowly; The big mixed gold disappears quickly, and the small mixed gold disappears slowly. Depending on the disappearance of the gold channel, the fineness of gold jewelry can be determined by comparing the cards.
How to quickly identify the authenticity of gold jewelry? Learn these points and you can easily handle them at home. P>
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