Alloy refers to a mixture of metals; often describing the non-gold metals in a gold mixture ie.14K is 58.5%gold and42.5% alloy.

Carat refers to a measure of weight used for precious stones, where .20 gram equals 1 carat and 5 carat equals 1 gram. The term and the weight come from the ancient near east where a carob seed was used as a unit of weight; something would weigh several carobs, i.e. carats.

Karat is an expression of gold purity, 24 karat being pure gold. Divide the karat value by 24 to find the percentage of purity, i.e. 14 divided by 24=.583 or 58.3%. Expressed as “fineness” leave the number as a decimal, ie.18K=750 or 75% gold.

GOLD: As explained, the purity of gold is expressed in karats, or the number of parts out of 24 that are pure gold. Most jewelry sold in the United States and Canada is 14 karat, or 58.3% pure gold. 10 karat gold is 41.6% pure gold and 18 karat is 75%. You may occasionally find 12 karat gold which is 50% pure gold.

All jewelry items should be stamped with the karat and a trademark of the manufacturer. The laws governing the stamping of gold are very strict and well enforced. Some genuine gold jewelry may not always stamped with its quality, also there are certain stamps that appear to denote karat gold but in reality do not. Take caution when purchasing jewelry that is not stamped. The most commonly confused stamp is “18KHGE”, which means 18 karat heavy gold electroplate or items that are only plated. Another stamp is “14KP” which means 14 karat plumb gold, or gold that is 14 karat or better. The 14KP stamp came to be used when stamping laws were revised to reduce a permissible error. The old law allowed 1/2 karat variation in quality, while the new law only allows a .003 error in the gold mixture. The “P” in 14KP was added to denote compliance with the new law and the 14KP stamp is still in use today. The absence of the “P” does not mean that the gold is of lesser quality than the gold stamped with 14KP. Other stamps to look out for, if looking for quality gold items are the words “overlay”, “filled”, “rolled”, or “plate”. “Overlay” means electroplated over a base or non-gold metal, “filled” can mean the same thing as “plate”, “rolled” and “filled” can mean that the gold has been applied mechanically and is up to 1/20th of the total weight of the article.

STERLING: Sterling is now a legal term meaning 925 parts out of 1000 are pure silver. It does not matter what metal, or combination of metals make up the other 75 parts.