The fineness of gold

The purity of gold and its products is called 'finished' or 'fineness'.　　 More than 200 BC, the Greek mathematician Archimdes was worried about judging whether a crown was made of pure gold. When he was bathing in the bathtub, he discovered what later generations called Archimedes's law of specific gravity: the purity of gold and its products that are immersed in liquid is called'formation' or'coloration'.　　 More than 200 BC, the Greek mathematician Archimdes was worried about judging whether a crown was made of pure gold. When he was bathing in the bathtub, he discovered what later generations called Archimedes's law of specific gravity: an object immersed in a liquid receives upward buoyancy; the buoyancy is equal to the weight of the liquid it displaces. Thus, it was successfully confirmed whether the crown made by the king was made of pure gold. So, how can the purity of gold be expressed? 1. The national standard gb11887-89 for expressing the purity of gold in k gold stipulates that the gold content of each open (the abbreviation of English carat and German karat, often written as k) is 4.166%, so the gold content of each open gold is (in parentheses, the country Standard): 　　8ku003d8*4.166%u003d33.328% (333‰)　　9ku003d9*4.166%u003d37.494% (375‰)　　10ku003d10*4.166%u003d41.660%(417‰)　　12ku003d12*4.166%u003d49.992 %(500‰)　　14ku003d14*4.166%u003d58.324%(583‰)　　18ku003d18*4.166%u003d74.998%(750‰)　　20ku003d20*4.166%u003d83.320%(833‰)　　21ku003d21*4.166% u003d87.486%(875‰)　　22ku003d22*4.166%u003d91.652%(916‰)　　24ku003d24*4.166%u003d99.984%(999‰)　　24k gold is often regarded as pure gold and becomes 1000‰, but the actual gold content is 99.99%, which is 23.988k.　　 2. Use words to express the purity of gold. Some gold jewellery is marked with words, and its stipulation is: pure gold-the gold content is not less than 990‰, and the gold content of thousand feet is greater than 990‰.　　 my country has regulations on the imprints and identification plates of gold products. Generally, it is required to have the code of the manufacturer, the name of the material, the imprint of the content, etc., and the products without the imprint are unqualified. The same is true internationally. But for some very small products, it is also allowed not to mark. 3. Use fractions to indicate the purity of gold. For example, if marked as 18/24, the color is 18k (750‰). If marked as 22/24, that is, the color is 22k (916‰). 4. Use Arabic numerals to indicate the purity of gold, such as 99- -Means pure gold such as 999-- means one thousand pure gold