Pricing
Gold is a precious metal that does not change in color, rust, corrode or fade and it can be molded to any shape. The value of your gold is determined by two criteria: Weight and Purity.

Weight
Precious metals are measured in ounces by an ancient troy standard. This standard is also used by pharmacists and medical professionals:

1 troy ounce = 480 grains = 20 pennyweights = 1.097 avoirdupois ounces = 31.103 grams

Purity
Gold is a very soft metal. To strengthen it, gold is often mixed with one or more additional metals called alloy. Alloys are usually copper, silver, or nickel. These alloys not only strengthen the gold but they also determine the color of the gold. For example, yellow gold will contain copper, and while gold will have nickel, zinc and copper mixed in. With these concepts, gold can come in many colors such as pink gold (also known as rose gold), or purple gold, etc.

The purity of gold is measured from 1 to 24 karats. 24 karats. 24 karat (24K) is the purest form of the metal, meaning it is 100% gold with no alloy. 18K gold means 18/24 karat, which is 75% gold and 25% alloy. Therefore, the lower the karat in gold means there is a greater amount of alloy. In the United States, an item must be at least 10K to be called gold. Jewelry or items less than solid 10K are considered costume jewelry and would not be eligible for trade.

You could be sitting on a gold mine!