When a goldsmith makes gold jewelry, he first puts the gold given to him by the customer on the scale, and then puts it on a thick hardwood board. There is a charred pit on the board. Put the gold in the pit and melt it with an oxygen lance. After melting, the gold is poured into the selected jewelry model (made of gypsum) and then pressed with yellow mud. After pressing, wait for a period of time, immediately knock off the yellow mud and gypsum, take out the molded gold jewelry, clean it in nitric acid solution, and finally polish it with a polishing machine, so that the goldsmith can put the jewelry on the balance scale to show it to customers again after finishing his homework. The original price of gold is relatively heavy, so it can be said that it will not be less than one milligram after being made into gold jewelry. The whole process of making jewelry is introduced above. Customers who come to make jewelry have been watching with their eyes wide open and have never found that gold has been stolen or exchanged. Then, they pay the processing fee and leave with the finished jewelry.

In fact, gold was stolen in the process of counterfeiting, at least at 10%. In other words, at least 1g of gold was stolen, and the stolen gold was replaced by other metals, and the finished gold jewelry became low in color. But the customer can't find the stolen process. Even if a few pairs of eyes are staring at it, or even photographed with a camera, the goldsmith will steal the gold from the customer, but the customer still can't find it. What's his mystery in this?

The mystery lies in the hard wooden board used to hold gold. The main secret is the burning pit on the board, and the article begins here. It turns out that a hole has been drilled in the side of the pit bottom with an awl. Jewelry goldsmiths have calculated the volume of the hole (containing gold) and then covered it with charcoal ash; On the other side of the pit bottom, obliquely upward, make a hole with an awl, and put in the fake gold refined by the jeweler himself, the weight of which is the weight that the hole at the lower side can hold gold. Generally speaking, the volumes of two holes are equal. Then, the orifice is also covered with charcoal ash.

When someone comes to make jewelry, the goldsmith will weigh the gold given by the customer and put it in the prepared wooden pit. First, when the gold is burned to melt, aim the musket nozzle at the place where the hollow hole at the bottom of the pit has become thinner and blow it away, and the gold will flow into the hollow. Then, blow the spray gun head obliquely. When the jeweler dips borax into the flame with a small stick to support combustion, scrape it gently with a small stick and cover the hole full of gold with charcoal ash. At this time, the gold in the pit had already melted into beads, and the goldsmith gently turned the gold beads and burned them with torches. Deliberately roll the gold ball to the edge of the hole where the original holiday gold was taken, blow off the charcoal ash blocking the hole with the spray gun nozzle, aim the flame at the position of the fake gold and burn it. The melting point of fake gold is lower than that of gold, and it only needs a high temperature of several hundred degrees (the melting point of gold is 1064.342℃). 20: 00), the fake gold will flow out immediately and mix with the real gold. The goldsmith kept rolling gold beads and burning them with flames. This completed the whole process of stealing gold. Because the flame emitted by the torch is particularly bright and oxygen is blown, the light emitted is particularly dazzling, and the eyes can't see clearly at all. So how many pairs of eyes staring at gold were stolen. The author has done experiments, aiming the lens at the wooden pit when making, and failed to find any doubts, that is, slowing down the lens observation and seeing no defects.

After the process of stealing gold is completed, the goldsmith pours the compact beads into the plaster model. Say that finish, I threw the wooden plate aside. At this time, people's attention has been focused on the plaster model, and no one will pay attention to the board again. It was not until the whole process of making gold jewelry was completed that the goldsmith took the gold jewelry to the scale and showed it to the customers. Seeing that there was no shortage of gold at all, the customer paid the processing fee and left safely with the finished gold jewelry. So people are often robbed of gold and kept in the dark.

Generally, goldsmiths have several boards, and some boards have burning pits on both sides. Each template represents a different gram weight. Designed a board and stole 1 gram of gold. One steals 2 grams, one steals 3 grams, and so on, all marked. For example, the customer takes 30 grams of gold to play with jewelry, and the goldsmith takes out 3 grams of boards to use. If the customer takes 20 grams of gold to play with jewelry, the goldsmith takes out 2 grams of stolen boards to use. If the customer plays with 1 0g gold, the goldsmith uses10g stolen board. Goldsmiths usually steal from customers 10% to 30% of gold. The amount of stolen gold is directly related to the quality of business. Sometimes a few customers come to play with jewelry a day, and the goldsmith can steal ten to dozens of grams of gold. Plus the processing fee, the daily income is considerable.