Chapter 178: Really big local tyrant (guarantee 5)
"Come on, young man, this is the spot gold I bought from the bank. Can you take a look at it? Some of them have black spots, and some have red spots. The bank said there is no problem, but I don't really believe it!"
The last aunt took out a big bag with many things packed in plastic.
At a glance, Chen Wenzhe discovered that this was really a wealthy man.
There are gold bars, gold coins, and silver coins inside, and there are quite a lot of them.
"Don't worry, show it to aunt. There are so many things, and I'll pay for the appraisal."
"No, one appraisal, no matter how many items there are, counts as one."
If it were calculated one at a time, she might have to pay him twenty to thirty thousand for these things.
Chen Wenzhe would not do such a black-hearted thing.
"You're a nice young man. There are some problems with these. You can take a look at them and keep an eye on them. I'll help you get people to buy the bracelets and I will never let you suffer."
Chen Wenzhe was happy when he heard this: "Did you buy these things from a regular bank? I mean, did you buy them at a bank, or did someone sell them to you outside?"
"I bought them from a bank. At first, there were only a few problems, so I didn't pay much attention to them. Later, I found more and more problems, and the bank didn't give any explanation. You can identify them so that I can trouble them."
Looking at the aunt's expression, Chen Wenzhe knew that the bank should have given an explanation, but she no longer believed it.
In this case, let’s give her a good look.!
The first thing I looked at was the gold bar. Sure enough, there were red spots on it. Then I took out a set of silver coins.
Many of them have black spots. Looking at the gold coins, there are red spots again.
Chen Wenzhe was sweating a little. These are problems. How many of them are problem-free?
"Can you remove the outer plastic seal?"
"Okay, just take it apart!"
Chen Wenzhe opened a version of the gold coin and when he weighed it, it turned out to be pure gold.
You can use a magnifying glass to see that there are indeed red spots on it, which are formed after iron oxidation.
But gold coins are pure gold, so where does the iron come from?
"Auntie, there should be nothing wrong with the gold coins. They are pure gold. You can go to a gold store to measure them. It's not troublesome to check the density. As for the red spots, they are indeed rust left after iron oxidizes and rusts!"
"The gold coins are fine, but are they rusty?"
"Yes, the gold coins are fine, at least this one is fine. If I guessed correctly, these should be fine. They are all genuine products. They are products produced by a national bank, so they should be fine."
After reading a few more times, Chen Wenzhe roughly understood what was going on. This problem was not an isolated case.
I often see news like this, saying that someone bought an investment gold bar with a fineness of 999 at a bank, but it turned rusty without opening the seal!
I obviously chose to buy physical gold in the bank for insurance, so how could it get rusty?
And according to common sense, only iron will rust, right?
Are the gold bars fake? Is there iron hidden under the appearance of gold?
If you do a random search on the Internet, you will find a lot of situations like this.
What's even more serious is that in addition to investment gold bars, even pure gold commemorative coins, which are legal tender, have become rusty.
The so-called rust mostly refers to iron items in daily life. In a humid environment, iron oxide is produced after oxidation.
The most direct effect of this chemical reaction is to make the original metal lose its good properties.
Therefore, rust has never left a good impression on everyone, especially the dull red color of iron oxide, which is often used in the background of some horror movies, making people habitually have a bad feeling.
One of the important reasons why many people suspect that gold products are gold-plated iron is that the "rusty" color of gold is almost exactly the same as iron.
Once this kind of rust appears, people's first impression is that the gold is fake!
The gold in many people's hands rusts, and the main phenomenon is "red spots".
The main phenomena of silver rusting are "white spots", "white haze", "yellowing" and "blackening".
So, if it is really forged from iron, why are the rust colors of gold and silver different?
Let’s first look at gold. As one of the most stable metals in its natural state, gold often gives people the impression that it can last forever.
Especially in some ancient tombs that are thousands of years old, lacquerware, silverware, bronze, and silk can hardly withstand the erosion of time. Only gold still maintains its original appearance when it is unearthed.
So in comparison, the gold bars and gold coins we buy now can be said to be more mature in craftsmanship and have higher gold content. Why do you think that today’s gold products are not as durable as unearthed cultural relics?
In early countries, gold and silver coins were mainly used for export. If the gold coins really have "quality problems", it is likely to affect the country's credit.
For this reason, in 1989, the Gold Coin Corporation and the United Mints conducted an exploration into the causes of "red spots".
After collecting and analyzing the erythema samples, it was found that its main components are silver and iron, which means that the red color above is indeed rust caused by iron.
However, after testing the gold coins, it was not found that they contained silver and iron. So how did these silver and iron appear?
After simulating the coin-making process, the testers finally locked the problem in the production environment and the coin-pressing mold.
Due to the metal dust pollution in the production environment, the coin body will be stained with trace amounts of silver and iron before packaging.
These impurities, under specific temperatures and humidity, will produce oxidation reactions, eventually leading to the appearance of erythema.
Testers deliberately adhered trace amounts of silver powder and iron powder to the gold coins for testing.
Under conditions of 35-50 degrees Celsius and 70-85% humidity, similar red spots appeared in just 3 days and became larger and larger.
In other words, as long as impurity contamination on finished coins is eliminated, the appearance of red spots can be prevented.
Of course, removing impurities requires more capital investment, and the prices of most common gold coins and investment gold bars are close to the price of gold. Therefore, from a cost perspective, the premium is not enough to support a more stringent process level, which has led to the fact that erythema cannot be used so far.
Completely eliminate it.
There are more problems with silver coins. First of all, the stability of metallic silver is not high, especially pure silver. In the natural environment, it can react with a variety of substances and is easily oxidized. This is also true for some silver jewelry.
It doesn't take long for it to turn black.
After silver comes into contact with sulfide, it will first turn yellow and then turn black. The white spots are the silver chloride crystals produced after the silver reacts with chlorine-containing substances.
If you encounter a humid environment, the speed of these reactions will only be faster.
When the production environment is not high, many silver coins are contaminated before leaving the factory.
Therefore, as long as it is not stored properly, even if it is kept intact, it will still oxidize and change color under certain circumstances.