Used jewelry is valued by its weight and by its quality. Those pieces that are heavy will get the most amount of money, as well as those pieces that are pure gold. Common types of karat quality include 10k, 14k, 18k and 24k. The purest form of gold is considered to be 24 karat. To estimate what you will get when you sell used gold jewelry, you will want to visit commodity websites that display the latest prices on gold. These rates change every minute and you will want the most current information when you are ready to sell your items. This data will also aid you in your selection process, as it will help you eliminate buyers that are providing you with low quotes.