Gold jewelry never goes out of style, and for good reason, because gold is as wearer-friendly as it is beautiful. Pure gold doesn't react with other elements to create tarnish, the residue that accumulates on some metals before transferring to your skin as a stain. Sometimes people have allergy or staining problems with metals that are combined with gold, but the gold itself is rarely a problem.

Gold can be worked into nearly any shape, including tiny strands that do not break easily. One ounce of gold can even be hammered into an ultra thin sheet that's ten feet square. Gold can be manipulated nearly any way the artisan desires.

How Pure Is Your Gold Jewelry?

Chances are the ring on your finger is marked 18K, 14K, or 10K, with the K standing for karat, the system used to describe the percentage of pure gold an item contains. The higher the karat number, the higher the percentage of gold in your gold jewelry.

• 24K gold is pure gold.

   

• 18K gold contains 18 parts gold and 6 parts of one or more additional metals, making it 75% gold.

   

• 14K gold contains 14 parts gold and 10 parts of one or more additional metals, making it 58.3% gold.

   

• 12K gold contains 12 parts gold and 12 parts of one or more additional metals, making it 50% gold.

   

• 10K gold contains 10 parts gold and 14 parts of one or more additional metals, making it 41.7% gold. 10K gold is the minimum karat that can be called "gold" in the United States.

European Markings

European gold jewelry is marked with numbers that indicate their percentage of gold, such as:

• 18K gold is marked 750 to indicate 75% gold
• 14K gold is marked 585 for 58.5%
• 10K gold is marked 417 for 41.7%

Other Markings on Gold Jewelry

The karat marking on your gold jewelry should be accompanied by a hallmark or trademark that identifies its maker. The item's country of origin might also be included.

Why Are Other Metals Mixed With Gold?

You'll find examples of pure gold jewelry, but pure gold is soft and isn't practical for daily wear. Other metals are mixed with it to make it more durable (and to lower its cost).

Adding other metals to the mix also allows metallurgists to change the color of gold. Palladium or nickel can be added to create white gold. Adding copper produces a rose or pink tint, while silver gives gold a greenish cast.

When metals are added to the gold the result is an alloy, a blended mixture of the metals that you can think of as a very expensive cake batter. Solid gold is a term that can be used to describe an item that's at least 10K (in the US) gold all the way through. Even though it's a gold alloy--18K, 14K, or anything down to 10K--it can be called solid gold.

When Gold Is Used as a Coating

There are many ways to mechanically apply a coating of gold onto a much less expensive metal, reducing the item's cost. The thicker the layer of gold, the less likely it is to wear away easily and expose the metal underneath.

Gold Filled Jewelry

Newer gold filled items have markings that indicate how much and what type of gold was used for the layer. A marking that says 1/20 12K G.F. means that the jewelry is at least 1/20th 12K gold by weight.

Gold Plated Jewelry

The gold layer in gold plated jewelry is typically thinner than the gold in gold filled jewelry, so it usually wears away more quickly. Plating is done in different ways.

You might see terms such as gold washed used to describe a very thin layer of gold--one that won't be very durable.

So What Should You Buy?

Solid gold is durable, so it is a better choice for jewelry you'll wear regularly. If you have allergies to nickel or other metals, choose items that have high gold content, such as 18K or 22K gold jewelry.

Gold filled or plated jewelry is suitable for jewelry that you wear occasionally. Everyday use would eventually diminish the gold layer, exposing the metal below, which might stain your skin or cause an allergic reaction.

For pieces that will last a lifetime and beyond, buy the highest quality gold your budget allows.