Not to be trapped in the first place not buy a gold watch in questionable places, and making the purchase, take care that the seller gave you all the necessary documents in case of return of defective goods.
Because a gold watch for a long time are in contact with the surface of the skin, then it should not show any irritations. Gold is only in very rare cases can cause an allergic reaction, so if the skin irritation, it means there is reason to doubt the authenticity of the gold.
This metal is extremely resistant to attack by acids. Dissolving gold may only "Aqua Regia" - a concentrated mixture of nitric and hydrochloric acids. Can test the quality of gold by rubbing the product in hand for about a minute. At low levels of precious metal you will have a dark blue trace.
There is one easy way to determine the quality of gold jewelry is to put it four hours on a piece of fresh bread. A high carat gold will not change its type, and the forgery will be covered with characteristic dark spots.
You can use home chemistry, which is in almost any home – vinegar and iodine. As in the case of "Aqua Regia" substandard products in contact with them darken.
Another way to test the quality of gold products will want to use a few, but, nevertheless, it is quite effective. This should hold it on the surface of the unfired ceramic tile, while real gold will leave a gold line, and after the fake will remain gray or black streak.
Advice 2: How to determine the quality of gold
Some people arrogantly called gold filthy lucre, or associate it with an idolatrous Golden calf, worshipped by the Gentiles. Although you probably have gold jewelry. People have family wedding rings. Young people prefer small rings, earrings, chains and pendants. People solid you can see more weighty jewelry of gold - necklaces, bracelets, chains, watches, cigarette cases. When choosing gold jewelry, a question arises about determining the quality of the precious metal.
You will need
- - a magnifying glass.
Before purchasing jewelry made of gold , try to determine the quality of the material visually. In jewelry use is not pure gold, but alloys with other metals. Included in gold ornaments impurities give the products appropriate shades. It is known that cobalt color gold red. Nickel, platinum and palladium contribute to the appearance of white shade, copper – yellow. Located at the peak of the popularity of gold jewelry rose color are made of alloy of gold, silver, copper and zinc. The fashionable and extravagant jewelry black gold is an alloy of gold, chromium and cobalt.
Armed with a basic magnifying glass, look on the back side of the high-quality gold decoration of the state assay brand. His imprint can be both combined and separate. In the first case, in one frame combined print head girls in kokoshnik and the digital sign sample, for example, 585 (means 1 gram of the metal is 58.5% of pure gold). Moreover, to the left of the female head, turned to the right, you will see under a magnifying glass letter. She is assigned to the territorial state inspection, branded jewelry product of gold.
If you want to buy, such as earrings, you will find a separate hallmark. On one part of the product will show off the profile of the lady in the headdress, and on the other side – the digital sign sample. Recall that in the Soviet times, hallmark has served a five-pointed star with the symbols of the epoch - a sickle and a hammer. Both Russian and imported products from gold, which are sold in our country, be sure to look for a purity mark.
Also, you're considering gold jewelry, in addition to the assay mark, find a printed list of names of the manufacturer. Here the first digit is the year of the marking of the product, the letter after the number indicates the cipher of gosinspekcii, and the remaining 2-3 letters – encoded name of the manufacturer. As you can see, quality gold will talk about themselves without reserve the information you need.
View information about jewelry and its manufacturer for a sealed label. Professionals determine the quality of gold by the method of cupellation, the method of assay stone or drip. However, the use of these methods may entail a violation of the surface layer of jewelry that the average buyer is unacceptable.
In order not to run into a fake, buy gold jewelry only in large jewelry stores, branded, sealed.
The cheapest gold can be purchased in Greece, Turkey or in retail outlets artisanal cooperatives, for example, in Novorossiysk.
Advice 3: How to dissolve gold
Gold – a chemical element, designated by the Au (from the Latin word "Agim"). Represents a very heavy metal (density is 19.32 grams/cubic centimeter) yellow. Sometimes it is necessary to dissolve the gold. How is it done?
You will need
- - concentrated hydrochloric acid;
- - concentrated nitric acid;
- - reaction container (flask or beaker);
- - a piece of gold (scrap jewelry, gold foil).
To dissolve gold, you can use methods which are still widely used in industry for gold mining and recovery of alloys. But hold them dangerous, as used solutions of potassium cyanide and sodium cyanide are the strongest poisons. These methods are based on the formation of soluble "cyanoaurate": [Au(CN)2]-.
You can also carry out the reaction of gold with fluoride, but it should be carried out carefully as the reaction takes place at very high temperatures (300 to 400 degrees), and the fluorine – poisonous and extremely active substance.
A fairly simple and safe way - the dissolution of gold in the famous "Aqua Regia". Mix in the reaction vessel with hydrochloric and nitric acid in a weight ratio of 3:1.
Throw a piece of gold, watch the progress of the reaction. Relatively quickly (even at room temperature, without heating) it will start to shrink in size, until dissolved completely.
Why did this happen? Under the influence of nitric acid some of the chloride ions present in hydrochloric acid, turned into highly active atomic chlorine. And he reacts with gold forming a so-called. "chloraurate-ion":
2Au + 3Cl2 + 2Cl− = 2[AuCl4]−
2Au + 3Cl2 + 2Cl− = 2[AuCl4]−
The great scientist Niels Bohr, leaving his native Denmark in the period of Nazi occupation, dissolved the gold medal winner of the Nobel prize in Aqua Regia. Returning after the war, he singled out the gold from solution by chemical means, and it made an exact copy of the medal.
Concentrated nitric and hydrochloric acids are very corrosive substances! Working with them, strictly observe the safety rules. It is better to use rubber gloves.
Pure gold is exceptionally malleable, in this respect, it is out of competition. It is possible to make thin plates ("gold leaf" gold). It can be pulled into thin thread, almost invisible to the naked eye. Along with this, it is indispensable in microelectronics (plated contacts, connectors, surfaces Board). But the main advantage of gold is its chemical inertness. Due to this it is used as a means of payment foreign exchange reserve.