Gold is one of the most precious metals in the world. It has been used in jewelry making for several thousand years because of its high value and high malleability (ability to mold and bend into shapes). Gold doesn’t fade, rust, or corrode, and has a high resistance to tarnishing. Its luster makes it the most important metal in jewelry making.

How is gold purity measured?

Gold purity is measured in Karats, or for European measurement, in fineness. To understand Karats, you must know that gold can be alloyed with other metals. There are numerous reasons for alloying, whether its to make the gold stronger, or getting more metal to work with while using less gold (which is more expensive than most metals). Nothing less than 10-karat gold can be legally marked or sold as gold in the United States.

Pure gold is 24K(arat). Lower karats will tell you the percentage of pure gold used in the piece of jewelry. It’s simple math really. 18 K gold, divided by the 24 K (pure gold), is 75% pure gold. (18/24 = 75%). Use the chart below.

How do other metals change the color of gold?

Alloying gold with other metals has different effects, depending on the types of metals used. Alloying can strengthen the gold for jewelry, as well as change the color of it. The amount of color change will depend on the amount of other metals used in alloying.

• Yellow Gold – comes from alloying with Copper and Silver
• White Gold – comes from alloying with Nickel, Zinc, and Copper
• Green Gold – comes from alloying with Silver, Zinc, and Copper
• Rose Gold – comes from alloying with Copper and Silver