Ebay is a fantastic place to buy fine jewelry (gold or platinum, with or without diamonds or colored gemstones).  When I list fine jewelry, the bidders are often people buying for their shops; they buy on ebay because they can find nice pieces at prices much lower than they can get from wholesale suppliers. Armed with a little basic information, you can easily evaluate ebay's fine jewelry listings and buy at bargain prices.

The first thing to know is what metal the piece is made of.  Ebay has cracked down on misrepresentation of gold jewelry in the past year or so, but it is still important to read descriptions carefully and EVALUATE THE SELLER'S FEEDBACK BEFORE BIDDING.  A seller with a large amount of feedback and a very low percentage of negatives is unlikely to misrepresent his or her merchandise.  On the other hand, I would be very skeptical of a seller with very few feedbacks or more than a handful of negatives.  Examples of accurate jewelry descriptions can be seen here. 

Mismarking gold content in the U.S. is a serious crime, so it is quite uncommon to find American-made pieces actually mismarked by the manufacturer.  That is not necessarily true in other countries, however, and extra care should be used in considering listings from sellers outside the U.S. 

Here are typical U.S. gold marks:

• 10K or 10KT or 416 - These are all marks identifying 10 karat gold (which is 10 parts gold and 14 parts other metal or .416% gold).  This mark indicates that the piece is 10K all the way through.
• 14K or 14KT or 585 - These marks identify 14 karat gold (which is 14 parts gold and 10 parts other metal or .585% gold).  This mark indicates that the item is 14K all the way through.
• 18K or 18KT or 750 - These marks identify 18 karat gold (which is 18 parts gold and 6 parts other metal or .750% gold).  This mark indicates that the item is 18K all the way through.

In addition to these karat marks, you occasionally see 9CT, 13CT, or 15CT, which are English marks.  These karatages have not been made in the U.S. but are common in English pieces.  You also occasionally see 20K, 22K, or 24K marks.  These marks are most often seen on pieces originating in Asia or the Middle East.

The lower the karat of gold, the harder the item will be.  The higher the karat, the softer and more pliable the item will be.  Except for very thick and heavy pieces, pieces made of higher than 18K will be easy to bend with your fingers.  For that reason, high karat gold is more often seen in pins, earrings, and necklaces than in rings (which are subjected to much more pressure and wear).

Descriptions that indicate DEFINITELY that a piece is not gold all the way through include:

• Gold-filled - This refers to a thin coating of gold on the outside over yellow base metal inside.  It is often stated as something like 1/20 14K, which means that 1/20 (5%) of the weight of the piece is 14K gold and 95% of the piece is something other than gold.
• Gold plate - Marks like 14K GP or 18K HGE mean that the piece is base metal with a very, very thin layer of gold on the outside.  GP means gold plate, and HGE means heavy gold electroplate. 

Not all gold plating is marked.  Other terms sellers sometimes use to describe jewelry that is NOT gold are "gold clad" and "goldwashed".  Except for antique pieces (items over 100 years old), the price for gold jewelry is generally much higher than the price of nongold jewelry.

People often ask me whether the fact that a piece is unmarked means that it is not gold.  Gold manufactured in the U.S. since the early 1900s is required by law to be marked with the gold karat mark.  Sometimes these marks have either worn away or been removed during sizing or repairs, so it is certainly possible to find gold pieces that are unmarked. 

Laws about marking gold in other countries vary with the country and the time period.  For example, it is common to find 19th century gold jewelry from England that has a karat mark.

Sellers of gold jewelry usually describe the marks on a piece of gold jewelry and often include a picture.  If the mark is not described or pictured, the listing should indicate how the seller knows the piece is gold.

I will be publishing another guide shortly focusing on how to evaluate the price of gold jewelry.