Beware of new scam! Gold becomes hard to tell if real or fake after mixing with this metal!

Audit expert: Kang Kai

Senior Engineer, Registered Civil Engineer (Geotechnical)

Recently, the international gold price has continued to rise, and gold has become a hot topic among people, frequently appearing on hot searches. How is gold formed? Why is gold so attractive? What are the difficulties in artificially synthesizing gold? What new "routines" have emerged in gold adulteration... Next, let us get to know this "investment star" from a scientific perspective.

Screenshot of Weibo hot search

How is gold formed?

Where does gold come from? This question has puzzled mankind for thousands of years. People have proposed many bizarre conjectures: some say it is concentrated sunlight, some say it is transformed from cheap metals... Of course, now we know that these conjectures are all unreliable. The earth itself cannot make gold, all gold comes from the sky.

Gold | Qianku.com

Simply put, gold comes from geological processes during the formation and evolution of the earth. The original gold came from the fusion of stellar nuclei in the universe, and then gradually gathered into the interior of the earth through the formation and evolution of the earth, and was brought to the surface through geological processes to form gold mines.

Supernova explosion | Baidu Images

According to relevant theories, heavy elements such as gold are produced in cosmic events such as supernova explosions or neutron star collisions. Under these extreme conditions, atomic nuclei form heavy elements such as gold through a rapid neutron capture process. This newly formed gold is then scattered into the universe with the fragments of the supernova explosion, and part of it is captured by the Earth and gathered in the Earth's crust.

In the early days of the Earth's formation, heavy elements such as gold gradually deposited in the mantle due to their high density, especially in the upper part of the mantle. Thermal convection in the mantle caused rocks containing gold to rise to the crust. These rocks cooled and crystallized in the crust, forming gold-containing ores.

Gold exploration in the field | Red Star News

When magma intrudes into the earth's crust and cools, minerals such as gold in it will separate from the magma to form deposits. These deposits may be vein-like, disseminated or massive, depending on the enrichment of gold and the geological environment. Under certain temperature, pressure and chemical conditions, gold will precipitate from the rock to form enriched deposits.

Over time, geological processes (such as plate movement, earthquakes, volcanic activity, etc.) and natural erosion (such as weathering, water erosion, etc.) change the structure of the earth's crust, exposing gold deposits to the surface or near the surface. These changes make gold available for human exploitation and use through mining and other methods.

Why do people love gold? There are many rare metals on the earth, such as molybdenum, lithium, tungsten, etc. They are not only very rare in the earth's crust, but also difficult to extract. Why is gold the only one that has become the "chosen one"?

Gold Jewelry | Qianku.com

First, it is difficult to mine. The gold content of general industrial gold mines is 2-3 grams per ton; rich ores are 5-50 grams per ton, and extremely rich ores can reach 50-500 grams per ton; poor ores are 0.1-1 grams per ton. Among the gold mines on the earth, there are not many rich ores and extremely rich ores. Generally, they are industrial mines with a grade of 1-2 grams per ton. That is to say, for every ton of ore mined, only 1-2 grams of gold can be obtained through metallurgical technology. Therefore, the average cost (professional term is "labor time") contained in each gram of gold is very high.

Second, it is easy to process and preserve. Gold is very flexible and ductile, and is easy to split and process. One gram of pure gold can be drawn into about 1,000 meters of gold wire. Gold is extremely malleable and can be hammered into very thin gold foil. Gold also has excellent physical properties such as excellent corrosion resistance, no oxidation, not easy to react chemically with other substances, and unchanged refining properties. It can be buried underground for thousands of years and still be golden after being dug up and processed.

Horseshoe gold unearthed from the tomb of Marquis Haihun | Marquis Haihun Museum

Third, it has a wide range of uses. Gold in industry is mainly used in electronic products. Precision electronic components and integrated circuits require high stability, conductivity, heat resistance and oxidation resistance, and gold and its alloys can meet these requirements. There is a small amount of gold in many electronic appliances such as mobile phones, computers, and televisions.

Electronic products | Qianku.com

Fourth, it has the function of preserving and increasing value. Due to its unique value and stability, gold is widely accepted as a universal form of currency. In ancient times, trade between countries often used gold as a means of payment. Even in modern society, although paper money has become the main currency in circulation, gold is still regarded as an important reserve asset and international payment method.

What is the difficulty in artificially synthesizing gold?

There is alchemy in the West and the legend of "turning stone into gold" in ancient China, both of which reflect the human pursuit of gold and the desire to synthesize gold artificially. Although scientists have successfully synthesized many elements in laboratory environments, it is still a huge challenge to synthesize gold artificially. According to existing knowledge, gold can theoretically be produced through the nuclear fusion process. In a laboratory environment, scientists can use equipment such as particle accelerators to generate gold through the collision of atomic nuclei.

However, this process involves changes in atomic nuclei, which requires extremely high energy and complex equipment to simulate the extreme high temperature and high pressure environment in the universe. However, the nuclear technology currently mastered by humans cannot be used to synthesize heavy elements such as gold. Even if the experiment is successful, it is costly and the amount of gold produced is negligible, which is far from meeting commercial needs. Therefore, due to technical and cost limitations, the dream of "artificial gold" is not feasible in reality.

There is a new trick for gold adulteration

As the "gold buying fever" continues to heat up, new "routines" have emerged in gold adulteration. According to media reports, some criminals add the metal "rhenium" to gold to pretend that it is pure gold jewelry. The price of "rhenium" is only a dozen yuan per gram. When mixed with pure gold, it is not only cheap but also difficult to be discovered.

The element "rhenium" appears as a silvery-white metal or gray to black powder, with a hard, wear-resistant and corrosion-resistant texture. Its density is similar to that of pure gold, and it cannot be distinguished well by conventional weighing, but its hardness and melting point are higher than pure gold. Professionals remind that the "rhenium" gold on the market cannot be distinguished by naked eyes or simple weighing. Therefore, when consumers buy gold, they should try to choose reputable brands and merchants.