Gold is one of the rarest metals in the world.the planet, since ancient times is considered a symbol of wealth, success and high status in society. In the periodic table D.I. Mendeleev it is referred to as Aurum, that is, "golden", and in the people it is also called "noble". And this is not accidental, because gold is an inert metal, practically does not enter into chemical bonds and does not form new compounds - behaves like noble layers of society.
In nature, gold does not occur in the form of "shining"coarse clastic rocks, but in the form of minute impregnations, grains of sand found inside the main gold-bearing rock. Sometimes grains of sand are so small that they can be discerned only with the help of special equipment.
But there are also nuggets, the largest ofwhich - "Desired Stranger" - was found in Australia and weighed about 75 kg. And when gold mining was conducted in the Urals, a sample weighing 35 kg, nicknamed the "Big Triangle", was found.
But gold enters the market only aftermulti-level cleaning. But even after enrichment the raw material contains in its composition a certain amount of impurities. Because of this, the first types of gold appeared, which differed in the breakdown - the percentage of metal in the product.
Government institutions as goldreserve the most pure samples of this metal. The percentage of the element in them is 99.999% per gram of substance. But the standard 1 kg bank ingot contains 999 grams of metal. That is the cost of the ingot divided by one thousand, can be seen on the gold and the stock exchanges of the world.
The gold sample is indicated on the product itself in the form of a small brand with the indication of quite specific numbers. There are two systems of samples in the world:
In the carat system, pure gold (a percentage of more than 99.9%) corresponds to 24 samples, and in the metric - 999th.
In its pure form, gold is verysoft, ductile and malleable material that literally "melts before your eyes" and is difficult to process. To make the gold raw material, various metals are added to it: silver, copper, cadmium, chrome, platinum and others. Thus, different types of gold, or rather its alloys, are obtained.
Depending on what element was added to theraw materials, are the physical properties of the alloy, as well as its color. The shade of gold products can be the most diverse, can range from gold, yellow and soft pink, to dark blue, brown and even black. All this ultimately determines the cost of jewelry and their aesthetic qualities.
Yellow gold is the mosttraditional and common in the world alloy. In it to noble metal in a different ratio of silver and copper. It is the amount of impurities that determines how much gold costs in the jewelry market. If the percentage of silver exceeds the amount of copper, then products of even lemon color are obtained. If there is more copper, then a red tint appears. The most common products on the market are 585 and 750 samples.
Red gold is obtained by adding to the alloya large amount of copper. In some products, the content of additives can reach 50% of the total mass. That is why all kinds of gold of a red shade are distinguished by low cost. It looks good with red gems - rubies and grenades.
Get green gold can be multipleways. The most common of these is the balanced addition of silver to the alloy. As the introduction of this metal changes the shade - the products acquire a green, yellow-green and pure white color. On this depends and how much gold is gold. If the percentage of silver reaches 30%, then a new mineral is formed - electrum.
