ISO 9202: 2019
Gold is a soft, dense, malleable metal with a bright yellow color that does not rust or darken in the presence of air and water. Chemically, gold is an intermediate metal and is one of the least reactive solid elements under standard conditions.
The metal can be found purely in nature in the form of granules or fragments among rocks, veins and alluvium. Gold can also be seen as a solid solution with other elements such as silver (electrom), as an alloy with metals such as copper and palladium, and even as entrained and trapped between materials such as pyrite. In unusual cases, gold has also been observed to be combined with elements such as tellurium.
The value of gold is due to its scarcity, easy usability, easy refining, resistance to rust and corrosion, distinctive color, reactivity with other elements; Properties less commonly found in other metals.
From the beginning of written human history, gold has always been a precious and popular metal that has been used for coinage, jewelry making, and artistic applications.
In addition to the use of capital and use in jewelry, gold has various other applications, including: dentistry, the production of stained glass and the electronics industry, and due to its high electrical conductivity, it is used in electrical wiring.
Gold is commonly used as an alloy with other metals. Copper is the most common metal used to make gold alloys, and other metals such as silver, nickel, and palladium are sometimes used. The percentage of gold in each metal object is called the gold grade, which is usually expressed as 24 units or 1000 units; For example, 18-carat gold (750) contains 75% gold and 900 gold contains 90% gold.
ISO 9202: 2019 specifies a range of grades of precious metal alloys (excluding solder) for use in jewelry.
It is important to note that there may be national legal requirements for the designation, marking and molding of finished products in the countries concerned.
The 2014 version has been canceled and the 2019 version of ISO 9202 will be used as the latest version.
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