Generally, the more gold silver ratio k, the color green; containing a large proportion of copper, the color is purple. In the early days of liberation, China's k gold was calculated at a rate of 4.15% per k. After 1982, it was unified with international standards, with a standard of 4.1666% per k. Use "k gold" to indicate the purity of gold The national standard GB11887-89 stipulates that each gold (English carat, German karat abbreviation, often written "k") gold content is 4.166%, so the gold content of each opening gold is (the national standard in brackets): 8k=8*4.166%=33.328%(333‰) 9k=9*4.166%=37.494%(375‰) 10k=10*4.166%=41.660%(417‰) 12k=12*4.166%=49.992%(500‰) 14k=14*4.166%=58.324%(583‰) 18k=18*4.166%=74.998%(750‰) 20k=20*4.166%=83.320%(833‰) 21k=21*4.166%=87.486%(875‰) 22k=22*4.166%=91.652%(916‰) 24k=24*4.166%=99.984%(999‰) 24k gold is often considered to be pure gold, which is "1000‰", but the actual gold content is 99.99%, which is 23.988k. Gold containing more than 99% pure gold is also known as "foot gold." Market And Applications,Fumed Silica Features And Applications,Use Of Fumed Silica,Silica Performance And Benefits Henan Minmetals East New Materials CO. LTD. , https://www.silicon-materials.com