In the world of gold jewelry, “karats” is a frequently used term. It is used to describe the purity of the gold used to make the piece. The word dates back to ancient Mediterranean and Middle Eastern civilizations that used carob seeds to measure the weight of gold. Today, this measurement is used interchangeably with the millesimal fineness system.
As the softest metal in existence, pure gold is not great for creating jewelry. It is often strengthened with zinc, copper, or silver, allowing it to retain its intended shape. Very rarely is pure gold used in jewelry and those unique pieces carry a 24K gold stamp. In other cases, the percentage of gold to alloy use determines purity.
Most gold jewelry in the U.S. is 10, 14, or 18k. A piece that is 18k is 75 percent pure, making it the most valuable of the three. Even when pieces have equal weight, the item with the higher number of karats will be more valuable. An 18k gold item will contain more yellow in the colored tint. Though 14k is more popular in the U.S., 18k gold is purchased by most European consumers.
Just because jewelry is stamped 18K does not mean it is. Laws vary between countries in terms of ensuring that these stamps are accurate. The U.S. is just one country that may not pursue a manufacturer for using a misleading stamp. Some countries mandate that gold purity be verified by a third party before a piece of jewelry may be stamped.
Those who buy gold coins are familiar with 24k gold because it is often used to make modern bullion coins. However, since it is often too soft for jewelry-making purposes, 18k is usually the highest number found on jewelry, though 22k is also available. Based on the current price of gold, anyone selling 18k jewelry should make a nice profit.