Manufacturer’s mark: the manufacturer’s mark in the form of letters or letters and digits. A manufacturer’s mark is assigned annually to each manufacturer registered with the State Inspectorate of Assay Supervision.

Standard mark: a special mark issued by the State Inspectorate of Assay Supervision confirming the fineness of the alloy.

Assaying:
determining, using several analysis methods, the proportion (weight content) of the main noble metal (gold, silver, platinum etc.) in the assayed alloy. It is used for further application of the standard mark. To put it simply, it is the process of determining the mass fraction of the main metal in the alloy. Example: 585’ gold means that 1,000 g of the alloy contain 585 g of pure gold; the remaining part consists of other alloy metals (copper, silver etc.).

Karat and metric system.
1 karat (kt) is equal to 1/24 of the total weight of the alloy, and 1 unit in the metric system is equal to 1/1000. 24 karats – 999.99` (pure gold); 23 karats = 958`; 22 karats = 916`; 21 karats = 875`; 18 karats = 750`; 14.04karats = 585`; 14 karats = 583.33`; 12 karats = 500`.

Precious metals.
Precious metals have high resistance to corrosion and are less subject to oxidation. Precious metals include gold, silver and platinum-group metals: platinum, palladium, rhodium, iridium, ruthenium, osmium.

White gold is an alloy of gold and platinum, palladium, rarely nickel.
Yellow gold is an alloy of gold and copper, silver, zinc and other.
Red gold is an alloy of gold and mainly copper.

Density.
Gold (Au) is one of the heaviest metals. Its density is 19.3 g/cm3. For example, the density of silver (Ag) is 10.5 g/cm3, the density of platinum is 21.45 g/cm3, the density of steel is 7.8 g/cm3.