Is gold sold per carat mass?

Gold is sold by its purity (Karat) and its weight The Karat (K) is the purity of the gold: 24K Gold = 1000 = 100% Gold 18K Gold = 750 = 75% Gold 14K Gold = 585 = 58.5% Gold........and so on By knowing the weight of the gold and the purity (Karat) you can determine how much mass is solid 24K gold and determine a price!!