Among all the jewelry, 750-proof gold is very popular today. The gold content in the alloy is higher (75%), therefore it is considered more prestigious. But at the same time, jewelry will require a careful attitude from its owner, since such an alloy is softer in comparison, for example, with products made from 585 gold .
Gold jewelry has been appreciated at all times. This is the oldest precious metal. Excavations of ancient pyramids and barrows find unusually beautiful and valuable gold jewelry. Due to its luster and color, this precious metal has always been considered the personification of the sun, which people worshiped during the pagan period. Gold jewelry identified power and power. Due to the "proximity" to the pagan deity, gold was endowed with extraordinary healing properties. It was believed that this metal will help get rid of epilepsy, heart attacks, inflammation of the heart muscle and other diseases associated with the heart. Perhaps this explains the Catholic tradition - to put a wedding ring in gold on his left hand.
What is gold?
This is a highly plastic and very soft metal that does not oxidize in air, is resistant to moisture, and is also immune to the effects of salts, alkalis, and acids. Pure gold is used in the jewelry industry for the manufacture of precious metal alloys. Gold alloy is an ideal material for jewelry production. Gold in its pure form is very soft, and alloys from it are more wear-resistant and durable. To enhance the hardness of the metal, it is mixed in certain proportions with other precious and less valuable metals. A sample of jewelry expresses the amount of gold (pure) in the alloy.
What is a 750 gold sample?
This alloy contains in its composition 75.5% of pure gold and additives, or the so-called ligature. Depending on the additives introduced into the alloy, the products can be of various shades - yellow, white, green, pink, red and even brown or black. The most popular is considered gold 750. Products from it can be made the most exquisite. The alloy is easy to polish and other processing. An adornment of such gold is a real work of art. Earrings, bracelets, chains, wedding rings are made from it. Gold of 750 samples has a color closer to the color of pure metal in comparison with samples below. However, when changing the composition of impurities, alloys can be obtained in the same sample, but the color will be different.
Carat system
In European countries, a carat system has been adopted, in which 24 carats represent 100% pure gold, but it is impossible to obtain it. Therefore, pure 999 gold is considered to be pure (“three nines”). 22 carats correspond to 917 samples, 18 carats - 750 samples, 14 carats - 585 samples, 10 carats - 417 samples, 9 carats - 375 samples.
Composition of gold 750
The composition of gold alloys in Europe and the countries of the former CIS is slightly different. Sample gold 750, as a rule, is three-component and contains silver and copper, less often rhodium, palladium, nickel, zinc can be added. We have more copper in alloys, silver in Europe. Thanks to this, our gold has a pronounced reddish tint, European - more yellow. Sample gold 750, in which the copper content is higher, is characterized by high strength.
Palladium or nickel may be added to the alloy to enhance hardness. Palladium is a very expensive noble metal. Thanks to him, gold acquires an exquisite soft shade. The cost of jewelry having such a composition is quite high; they are suitable only for true connoisseurs of precious jewelry. The price of products with nickel is much lower, such an alloy can magnetize.
Gold processing
To achieve high performance, a metal steaming method may be used. The solid solution in this case decomposes into various phases and the AuCu3 association is released.
Gold 750 tests perfectly during the processing, casting, brazing of links. Also, when working with vitreous enamel, the alloy can serve as a base. However, it should be borne in mind that the copper content in the alloy should not exceed 16%, otherwise the enamel quality will deteriorate, and after a while it will lose its brightness and beauty.
Semi-precious and precious metals in the alloy
Depending on the metals included in the alloy, it can be white or colored. The appearance of the product and its technological characteristics are directly affected by the percentage of copper and silver impurities in the alloy.
The alloy of gold and silver has a lemon tint. For an alloy of gold with copper, a pinkish or red color is characteristic. The melting point of gold with silver is a thousand degrees, with copper - slightly below nine hundred. During cooling, a solid homogeneous mass is formed, which then decomposes into phases.
According to the chemical ratio of the elements, alloy 750 is almost pure gold. If we compare it with test gold 585, then such an alloy lends itself much better to any processing.
Even repeated heat treatment does not affect the strength of the alloy of gold 750 samples containing copper and silver. Spontaneous cracking of a precious metal does not occur.
Gold 750 - it is prestigious and noble. Jewelry made from such an alloy is highly valued throughout the world. Jewelry from it is always relevant and not subject to fashion trends.