Basic knowledge of silver

1. Composition and chemical properties of silver: Silver is one of the heavy metals, with the English symbol Ag. Silver is silvery white, with a relative density of 10.49, a hardness of 2.5 ~ 3 and a melting point of 96 1℃. Chemical properties are stable, insoluble in alkali and most organic acids, soluble in nitric acid and hot sulfuric acid, but easy to combine with sulfide to form silver sulfide, which makes the surface of silverware black and white. It is very malleable (second only to gold) and is a good conductor of heat and electricity.

2. Content and expression of silver: The purity of silver is expressed in one thousandth.

(1) Thousand-foot silver: the silver content is not less than 990‰, and the stamps are full silver or S990 and silver 990.

(2)925 silver: the silver content is not less than 925‰, and the stamp is S925 or Silver 925.

3. The difference between Qianzu silver and 925 silver:

(1)925 silver is an international standard for silver ornaments, and 7.5% copper and other alloys are added to 92.5% silver, which greatly improves the luster, brightness and hardness of silver. Because of its enhanced hardness, it is mainly used to make fashionable silver jewelry with complicated technology.

Since Tiffany founded 925 Silver, 925 Silver has been internationally recognized as pure silver, recognized by all countries in the world, and is the international standard silver for silver ornaments.

Baiyin maintenance

Because of the active chemical properties of silver, silver will react with sulfur dioxide in the air to produce black silver sulfide, which will make the surface of silver ornaments oxidized black. Friends who have used silverware or worn silverware have had this experience. After a period of non-use, silverware or silverware is easily oxidized and discolored. When this happens, you don't have to worry. The following silverware maintenance methods can help your friends to relieve their troubles. Let your silverware (ornaments) restore the beautiful luster of silver.

1. You can add baking soda powder to clean water, then clean and wipe it, and then dry the water on silverware (ornaments).

2. Wipe it with silver cloth and silver paste [it should be available in general jewelry stores. It is particularly important to point out that silver cloth contains special potions and cannot be washed.

3. Rub some toothpaste on the jewelry with a soft cloth, then wash it with clear water and wipe it with cotton cloth. (recommended)

4. Soak the silverware or silverware in silver washing water, then wash it with clear water, and finally wipe it with cotton cloth and keep it dry. However, it is suggested that silver washing water should be used as little as possible, because silver washing water is a chemical product. Using the corrosiveness of silver washing water to clean silver ornaments will cause harm to silver ornaments for a long time.

5. When the silverware is not used, it is recommended to seal it with a sealed plastic bag to reduce contact with air and slow down blackening. Finally, remind everyone that it is best to avoid contact with seawater and hot springs. If you don't wear it, you can put it in a container that is isolated from the air, such as a flannel bag or a jewelry box, which will make your silver jewelry as new!

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Identification of pure silver

1. You see, the higher the color purity, the whiter the silver, and the jewelry surface looks even and shiny. If it contains lead, the jewelry will appear bluish gray; If it contains copper, the surface of jewelry will be rough and the color will not be moist.

2. The density of silver by weight is slightly higher than that of ordinary metal. Generally speaking, "aluminum is light, silver is heavy, and copper is not light or heavy." Therefore, it can be preliminarily judged whether it is silver by weighing. If the jewelry is large and light, it can be preliminarily judged that the jewelry belongs to other metals.

3. Check the hardness. The hardness of silver is lower than that of copper but higher than that of lead and tin. You can use pins to test the inconspicuous parts of jewelry. If the needle slips, it is difficult to leave traces on the surface, which can be judged as copper jewelry; If it is made of lead and tin, the trace is obvious; If the object has traces but is not obvious, it can be preliminarily judged as silver jewelry.

4. Listening to the rhyme sterling silver jewelry hitting the floor, there is no elasticity, and the sound is "bam bam". The lower the color, the lower the sound, and the sharper and higher the rhyming sound; If it is made of copper, its sound is high and sharp, and its rhyme is short and short; If it is made of lead and tin, the sound of falling to the ground is dull, short and inelastic.

5. Nitric acid method File a small gap on the silverware with a knife, coat the gap with nitric acid, and observe its changes. More than 95% of pure silver remains white, 80%-95% of silver turns black, 50%-75% of silver turns green, and the deeper the green, the lower it is.