1) Color discrimination: As the saying goes, gold "seven greens, eight yellows, nine purples and ten reds" presents different colors due to different types and components of impurities. Experts believe that 70% of jewelry with gold is yellow with blue, 80% is yellow with gold, 90% is yellow with purple, and 100% is red with gold. Pure gold is soft and generally not used to make inlaid jewelry. Therefore, any so-called 24K inlaid gold jewelry must be fake.
2) Weigh
What is the specific gravity of gold 19.3g/cm? 0? 6. Fineness has a great relationship with specific gravity. When the specific gravity is close to 19.3, the content of pure gold is higher. When the specific gravity is 18.5, the gold content is 95%, when the specific gravity is 17.8, the gold content is 90%, and so on. As long as you measure the specific gravity, you can know the fineness of the jewelry, but you can generally weigh it in your hand. If it is a little heavier, it can be felt because other metals with the same weight, such as silver, copper, tin and lead, have different weights. Compared with other metals, silver accounts for 45%, copper 46%, tin 38% and lead 59%. It can be seen that the gold body is small and heavy, and it will feel heavy if placed in the palm of your hand. Beware of silly light ornaments and carefully distinguish whether they are fakes or semi-fakes.
It is worth noting that many gold ornaments currently on the market are Asian gold products. The so-called second gold, in fact, there is no gold at all. It is an alloy material made of copper, aluminum, nickel and other metals, which has the characteristics of high hardness, wear resistance and no discoloration.
3) See Phonology
High-quality jewelry, thrown on the concrete floor, will have a dull click, which is a sound without rhythm and strength, commonly known as dead sound. On the contrary, low-quality gold ornaments thrown on the concrete floor will have rhyme, long shrill sound and slight rebound.
4) Apply both hard and soft
The higher the fineness of gold jewelry, the softer it is and the less elastic it is. Real gold will have faint traces when bitten by teeth or scratched by needles, and will not change color after being burned (not at extremely high temperature). The low-quality fake is the opposite.
5) Throwing method
Real gold will make a "poop-poop" sound when thrown on the table and the ground, while fake gold or lottery gold will make a sharp and clear sound.
6) Combustion test method
"Real gold is not afraid of fire", that is, it does not fade or dissolve at the high temperature of 1000℃, but begins to melt at 1063℃ but does not change color. Put the gold ornaments on the stove surface or tile and bake them until they are red. After cooling, the surface color remains unchanged.
7) Reagent method
That is, using 45% nitric acid to test: gold has no change, silver turns black, and copper bubbles and turns green. This is because the chemical properties of gold are stable, it will not be oxidized in any state, and it is also very stable in water, air, hydrogen sulfide or saline-alkali environment. Gold is hardly soluble in any single acid, but only in aqua regia (a mixture of hydrochloric acid and nitric acid with a volume ratio of 3: 1).
8) Check the stamp marking method
Gold ornaments produced by regular manufacturers are all printed with gold content and manufacturer's logo, such as 24K, 14K, etc. If there are no standard journalists, they are generally fakes.
Ten methods to identify the authenticity and color of platinum jewelry
1) See the color test.
Generally, it is divided into three colors according to the fineness, and blue, white and gray are the true colors with higher fineness; Blue, white and yellow are the components of platinum containing gold or copper, and the color is inferior; Silver is platinum with more silver components, and its fineness is lower than the above two. Pseudoquality black.
2) Fire test
Platinum can only burn red in general fire, but can't melt. After firing, the luster with fineness above 95% is consistent, the brighter it is, and the slightly black one with fineness around 70%. Fake ones will turn black and melt easily.
3) Weighing and weight testing.
The specific gravity of platinum is the highest among metals (265,438+0.4), which is 65,438+00% heavier than gold and also heavier than other metals. It is easy to weigh out by hand, and it is determined by color. If it's light, it's either fake or low in color. Further, a specific gravity test can be used, and the specific method is the same as the specific gravity test for identifying gold.
4) Listen to the voice test
When pure platinum is struck after burning, it makes a "Toto" sound without rhyme, while impure platinum makes a "Tintin" sharp sound with sound and rhyme.
5) testing stubble products
Cut the ornament in half with tweezers, and a cotton (sticky) stubble appears after bending. The higher the color, the softer the stubble, and the stubble with inferior color is brittle when cut.
6) Bend to see if it is soft or hard.
Platinum is as malleable as gold. It can be hammered into platinum foil with a thickness of only 0.0025 mm, and 20 such thin platinum foils are stacked together, which is only as thick as a page. Therefore, bending hardness can also be used as a test method.
7) Try adding salt to nitric acid.
Grind platinum on the touchstone, add a small amount of salt (just covering half of the golden path) to the platinum path, and then add nitric acid to the salt until the salt is completely absorbed by nitric acid. 15 minutes, and wash away the salt and nitric acid with clean water. If it is platinum, the fineness is above 95%, and the gold channel remains unchanged, about 90%. The gold channel changes slightly, and it is slightly blurred by about 70%. The gold channel turns dark gray and is corroded.
8) Mercury wiping test
The scientific name of mercury is mercury, which is commonly known as mercury in China. Using the characteristics of gold and silver absorbing mercury and platinum not absorbing mercury (normal temperature), the gold road was coated with mercury. If you don't absorb it, it means it's real platinum. If it is absorbed, it is a fake made of gold or silver.
9) Point gas lamp test
Platinum acts as a match and can be used to test the authenticity of platinum. Gas lamps are all lit with matches. If you put a piece of real platinum in the gas lamp, after a minute or two, the platinum will turn red and the gas lamp will be lit. If platinum is fake, it will not be red and the light will not be on.
This is because platinum has the property of accelerating many chemical reactions. It can be used as a catalyst, and it is difficult to directly combine coal with oxygen in the air at room temperature. But with platinum catalysis, it can combine slowly, release a lot of heat, make the platinum block turn red, and finally light the gas lamp.
10) hydrogen peroxide test
For example, platinum powder, put a little in hydrogen peroxide, is real platinum, and immediately white waves roll, decomposing a lot of oxygen, but platinum powder is not a little. If it is false, it will not change.
In the specific identification of platinum, the above methods can be used in combination, and the fineness can be determined after careful study.