Buyers know that the authenticity of gold products is confirmed by the presence of an assay mark, a test. But not everyone knows how this or that sample is determined, and that products are usually an alloy of gold with other metals.
Sample features
GOST establishes for gold samples - digital values showing the amount of gold in a kilogram of alloy. According to GOST, there are 40 gold alloys of 18 samples. For jewelry, alloys of 5 samples are used: 958, 750, 585, 583, 375. Gold 750, 585, 583 is the most common in Russia. There are also 333 samples for low-cost jewelry in a number of countries. All items are stamped with an assay mark, allowing you to find out the percentage of gold in them.
One hundred percent gold is designated 999 and has long been called pure gold. However, it is not suitable for creating jewelry, because easily deformed and scratched due to its softness. But money is invested in it.
Alloy 958 consists of three components - gold, silver, copper, it is quite soft. It is mainly used for wedding rings. The alloy has a beautiful bright yellow hue, close to the color of pure gold.
The 750-carat alloy is composed of gold, copper and silver, and may also contain nickel, palladium and zinc. Among the shades - greenish yellow, reddish yellow, white. Due to their lower wear resistance, 750-carat products are best worn for celebrations and special occasions.
Alloy 585 is also a three-component alloy. It contains 585 parts of gold and 415 parts of other metals (for example, 208 for silver and 207 for copper). Gold in this alloy is 58.5%. Depending on the ligature, the alloy can have different degrees of hardness, different melting points, different shades - reddish, pinkish, yellowish-zenish, white. The alloy has good solderability.
Gold 375 assay value has a muted reddish tint, and when the polish is lost, the item becomes grayish. Wedding rings are made from this alloy. Alloy 333 sample is unstable to oxidation and is slightly soluble in nitric acid.
A high sample does not guarantee a high quality product. Melting must be carried out in compliance with special technologies, otherwise there may be areas with a low gold content, and they may tarnish and corrode. The professionalism of the master is also important.
White gold
The ligature gives the alloy a certain shade: silver - yellowish, cadmium - greenish, copper - reddish and pinkish, palladium - steel whiteness, steel - bluish, aluminum - violet.
Impurities of various metals that give the gold alloy strength, wear resistance and other properties are called ligatures.
From an alloy of gold with palladium, nickel or platinum, the now fashionable white gold is obtained. It is common and noble. The common one is alloyed with silver, copper, zinc and nickel, and the noble one is alloyed with expensive metals palladium and platinum. White gold jewelry is generally more expensive due to the more time consuming labor-intensive work and the higher costs in making the alloy. Rhodium-plated white for a radiant cool shine and protection from damage.
