Gold is a precious metal that has an economic value of great importance, so much so, that in many occasions, people do not invest in anything else but this metal, which can be considered as a safe value, showing the importance of this metal.
When we are going to buy a piece of jewellery, what we must do is make sure that it is real gold. If we buy it in a renowned jewelry store, we will have no problem because the gold will be of the best quality, but if we do it in another store, it is important to make sure that what we buy is gold and not a bath.
The same thing happens when, for a gift or an inheritance, a piece, supposedly made of gold, comes to us and we want to sell it. Before doing so, we must make sure that it is really this metal and not an alloy, but… how do we do that?
The first analysis
The first analysis that we must carry out to check whether a piece is gold or not, is to observe it carefully. Normally gold pieces have a mark that indicates the purity of the gold or the karats it has.
If we do not find the engraved mark that indicates that the piece is gold, it may have been worn out or it may be a fake piece. Be careful! the fact that this engraving exists does not indicate 100% that the piece is authentic, fake pieces sometimes include this engraving as well in order to deceive the future buyer.
The next check to be made is that the colour of the gold is uniform and there are no signs in the areas of greatest wear of the appearance of another colour of metal.
Bite the gold
It is very common to see in western movies that they apply this method to recognize a gold coin, however, we recommend to be very careful with the teeth if we want to try to determine if a piece is gold or not with this system.
Applying this method, if it is gold, the metal can show cracks in the teeth since it is a soft metal, although it is not a foolproof method since there are soft metals that can receive a good gold bath and fool us.
The density test
The density test will allow us to refresh our knowledge of the institute and for this we will need a small scale, a millimeter container and water. With this method we can find out how many karats the piece of gold is that we want to check.
The first thing we must do is weigh the jewel, fill the container to the 0 mark and submerge the piece of gold and see the level it marks when we submerge the piece. In this case, we must see the difference between the water level (zero) before dipping the piece and the level after dipping it. Now, knowing the weight in grams, you can calculate the density that the jewel has.
- The 10 carat gold has a density of 11.57 gr/ml.
- The 14 carat gold has a density of 13.97 gr/ml.
- The 18 carat gold has a density of 15.58 gr/ml.
- The 24 carat gold has a density of 19,32 gr/ml.
This method is only valid for knowing what density gold has, not for verifying if the metal is actually gold. To do this, it is necessary to check first that the piece is really made of this precious metal.
The magnet test
Although the use of a magnet may seem a rudimentary method is very effective to know if the piece we have is gold, it can be very helpful. Sometimes, it can be a gold-plated ferrous material.
A small magnet may not be effective enough, but for that you must have a very powerful magnet, such as neodymium magnets, which are the strongest we can find on the market today.
As we already know, gold is not a magnetic metal and in case the magnet approaches the piece we want to check, it is confirmed that it is not real gold.
Recognizing gold using nitric acid
Gold can be very easily recognized with the nitric acid method. The problem is to be able to find this acid, although it is not impossible, nor illegal. What we have to be careful with is its manipulation, so what we usually do is ask the jeweler to use this test with the piece we want to know if it is gold or not.
To do this test you have to put the piece in a stainless steel container and apply a drop of nitric acid and wait to see what its reaction is.
- If it turns green, it means that the piece is made of another metal that is not gold or that it is simply gold-plated.
- If it turns white, it may mean that the piece is made of sterling silver and has been gold-plated.
- If the color that the piece acquires is gold, the piece is made of brass and has been gold plated.
- If there is no reaction, it is very likely that we are looking at a real gold piece.
Rubbing gold with ceramics
Este método consiste en frotar el oro contra una pieza de cerámica sin vitrificar. Dependiendo del color que deje en la cerámica la pieza metálica que estamos analizando, podrá ser oro o no. Si deja marcas de color negro no se trata de una pieza de oro real, pero si deja marcas de color dorado, es muy probable que se trate de una pieza de oro real.
This method consists of rubbing the gold against a piece of unglazed ceramic. Depending on the color left on the ceramic by the metal piece we are analyzing, it could be gold or not. If it leaves black marks, it is not a real gold piece, but if it leaves gold marks, it is very likely that it is a real gold piece.
As you have seen, these are very simple tests to recognize gold and that its verification does not take much effort. With them you will be sure if a piece is real gold or not.