Gold purity levels range from 10 karat gold, which is the least pure, to 24 karat gold, which is 100 percent pure. Less than 24 carat gold is always an alloy of copper, silver, or platinum with other metals. 10 karat gold is considered good for making jewelry while 21 karat gold is used for coins. Gold has been used for ornamentation and currency since ancient times. Gold is taken from nature at a rate of 1.7 billion tons per year. That's about one-tenth of one ounce of gold per person on earth! The word "gold" comes from the Greek oxys meaning "heavy" and goldos meaning "to glow." The Latin term for gold is aurum. Aurum means "fire" in old English. This is because people believed that gold had supernatural powers and could protect you from danger. Today, we know that it is its physical properties that make gold useful for jewelry, coinage, and industrial applications. There are several methods used to extract gold from its ores. The most efficient method is the electric furnace. It can process large amounts of material in a short time. A second method is the hydrometallurgical route which includes the Chlorination Process, the Cyanidation Process, and the Fermentation Process.