Gold prices have recently skyrocketed, and precious metals such as gold, 24-k gold, platinum gold, and 18-k gold have become a hot topic. A lot of people are saying, "what difference does it make?" how do you detect gold when it's recovered? For this reason, the journalist interviewed guo ying, director of the china geology university (beijing) jewellery college, asking him to read it out for everyone。
Gold, platinum, 18k
In short, gold is pure gold, platinum is a separate silver and white metal, while gold 18k is 75 per cent of alloyed gold mixed with other metals, each of which has characteristics。
Gold
Gold, chemical element symbol au, is known as precious metals. According to the national standard, gb11887-2024 precious metals purity regulations and naming methods, the purity of gold stipulates that au 999 kyats of gold shall consist of no less than 999 kyats of gold, which is the highest purity in the market; au 990 shall consist of no less than 990 kyats of gold, commonly referred to as full gold。
24k gold
In the market, we often hear 24k gold. In fact, it is a coloured gold product, theoretically 100 per cent gold, representing the highest purity. However, in the area of traditional jewellery, 24k gold is not common, as it is too soft in quality and prone to deformation, usually used for the production of gold bars, gold coins and better suited for investment preservation. At the moment, however, the 3d hardware technology has done a great deal to boost the 24k gold jewellery, which, through the electrolytic casting process, has addressed the pains of the traditional 24k gold jewellery, which is soft, heavy and symmetric, making it more fashionable, easier to wear and more durable。
Platinum
Platinum, chemical element symbol pt, is another independent precious metal. It is often mistaken for platinum, but it has no chemical connection to gold. The common platinum purity levels are pt990 (fatal platinum, 99% platinum) and pt950 (95% platinum)。
18k gold
18k gold is gold alloy with a gold content of 75% (18/24), while the remaining 25% is other metals such as silver, copper, thallium, etc。
Depending on the proportion of the added metal, 18k gold presents different colours:
18k platinum with white metals such as thorium and nickel (not more than 0. 3% nickel) showing white light - it is particularly important to remind you that the rings in the jewellery store, mostly 18-k platinum, are described as “white 18-k gold”, not platinum。
Silver and copper have been added to the 18k gold, which is common in yellow。
The gold of the 18k roses added more copper, presenting a charming pink. It is usually marked as “18k” “au750” or “g750”。
Recovery of gold
As the price of gold increases, both buying and selling involve testing. What methods are available to detect the authenticity and purity of gold
Kwok yong has described the following methods:
Fire test gold
The pyrotechnic method, known as the industry's “gold standard”, is the high-temperature smelting that separates gold from impurities and then recalculates purity. It's extremely accurate to reach 99. 99 per cent. However, this method destroys samples and is long-term in duration and requires specialized laboratories. This method is generally used by banks, large recycling facilities or when conducting arbitration tests。
X-ray fluorescent spectroscopy
This method is non-destructive and analyses the composition of the elements by stimulating the sample to launch signature x-rays. Its advantages are prominent, its detection is rapid, it can produce results in three to five minutes, and it does not cause damage to samples and it also detects surface purity. However, if gold has surface coatings (e. G. Plating or stains), it may interfere with detection results. It is particularly suitable for initial screening at a formal recycling shop and is the preferred method。
Density method
The density method measures the quality and volume of gold based on the akimid principle and then calculates the density (the density of pure gold is about 19. 3 g/cm3). This method is low-cost and simple to operate. However, if you encounter complex shapes, hollows or embedded jewellery, the error is greater. It is therefore more appropriate to detect simple gold bars and blocks, which are carefully used for jewellery。
Acid test
The acid test is a test of gold with nitric acid or perch water point, and purity is judged by chemical reactions. It is low-cost and allows for initial screening on site. However, this method risks corrosion and results are subjective and imprecise. Formal recycling facilities usually do not use this method, which can only serve as a primary screening tool。
Gold recovery attention
Select formal institutions
Kwok indicated that it was important to select an institution certified by cma/cnas when recovering gold. These institutions have specialized detection equipment and qualifications and can provide accurate results. At the same time, the institution is required to record every step of the video, from weighing to testing, and to produce a detailed test report in order to safeguard its rights and interests。
Fraud alert
Guo wing also warns against recycling points where prices are much higher than market prices. This is likely to be a trap; it is not easy to believe in roadside stalls or “high-price recovery” campaigns from informal channels and avoid losses due to greed and cheapness。
