The ring marked g18K refers to the metal composition and content of the ring. g refers to the metal, 18K refers to the content, meaning that the gold content of 75% of the gold alloy, commonly known as 18K gold. 18k gold is an alloy with a gold content of at least 75%, that is, an alloy with a gold content of 18/24, and the remaining 25% is other precious metals, including platinum, nickel, silver, palladium, etc. 18K gold is a low cost and more comfortable to wear a kind of gold jewelry.