If it is gold, there are three main reasons:

1 contact cosmetics. Some cosmetics have excessive mercury content, and mercury contact with pendants will lead to the fading of gold ornaments;

The second is contact with swimming pool water. Because the pool water is cleaned with disinfectant, the chemical components inside will react with gold;

Third, it will change color when it is placed with jewelry of other colors, such as diamonds and platinum. It is recommended to keep them separately.

If agate is red, the fading is even more false.

By the way, I'll tell you a little trick: how to distinguish between true and false jewelry.

How to tell the true from the false? In fact, it is really hard to see with the naked eye, and even experts can only see it roughly at most. However, consumers will not be deceived if they are not blindly greedy for cheap, buy carefully, or not buy.

Myth 1: Too much price comparison.

Solution: Some jadeites are beautiful and cheap, but they are often processed or fake. Some diamonds are very affordable and can be certified. In fact, the certificate may be fake, and we can't just look at the price.

Myth 2: the place of origin is cheap.

Positive solution: the place of origin is not necessarily cheap, even if it is cheap, not everyone will buy it.

Myth 3: Only the national certificate can be assured.

Truth: Many people think that certificates with the prefix "China" or "China" belong to the country, but they are not. In fact, as long as the CNAS and CMA marks on the certificate are recognized by China National Laboratory, they can be said to be national and can also be recognized by more than 40 countries in the world.

Myth 4: When buying gems, you must pursue perfection.

Solution: Even natural gemstones are inevitably flawed, such as emeralds, which are almost cracked.

Myth 5: Gems are hard and not afraid of falling.

Positive solution: Although the gem is hard, its toughness is not very high, and it is brittle, and it is easy to be damaged after colliding with hard objects.

Myth 6: South Africa has the best quality diamonds.

Truth: In fact, diamonds are produced all over the world, and there are good and bad grades. Similarly, diamonds in South Africa are mixed.

Myth 7: Diamonds must be purchased at VVS level.

Positive solution: buy diamonds from factors such as clarity, cut, color and weight. In fact, the cleanliness levels of VS and SI are also good.

Myth 8: "18K platinum" is platinum.

Solution: The correct name of "18K platinum" is "white 18K gold", which means that platinum contains 75% gold and 25% other metal elements.

How to tell the authenticity of jewelry?

1

Specific gravity test method:

There is a specific gravity liquid on the market, which is used to measure the specific gravity of precious stones. We can use a liquid with a specific gravity of 3.32 to test the authenticity of diamonds. The specific gravity of natural diamonds is 3.52, and all natural diamonds will sink when placed in specific gravity water, so any gem floating on specific gravity water can be sure not to be a diamond.

2

Penetration observation method:

The high refractive index of diamond, the higher the refractive index, the stronger the reflection and the lower the relative perspective. You can prepare a piece of paper with a straight line. The two unknown diamonds to be measured face down and cover a straight line. If you can see a straight line under a diamond, it is definitely not a natural diamond.

three

Hydrophilic method:

Diamonds have an "oil absorption" effect on oil, while fake diamonds do not. Rub the diamond on your face and rub it with your thumb. Your thumb will feel sticky and not easy to slip, while fake diamonds will make your thumb feel slippery.

four

Breathing test:

Natural diamonds have strong heat transfer ability and fast heat dissipation. Put the diamond to be tested close to your mouth, breathe gently, and let the diamond to be tested be covered with a layer of light fog. At this time, watch the evaporation of diamond fog immediately. If it is a natural diamond, the fog will disperse immediately, otherwise, the fog will stay on the fake diamond for a while before dispersing.

five

Size and weight:

The diameter of 1 carat natural diamond is about 6.50 mm (0.65 cm). Most fake diamonds are always far from natural diamonds under the same weight of 1 carat.