The purity and value of gold is determined by the karatage, which can be altered by the types of common metals that are added to the gold to lower its purity. Although many differences separate the highest 24K gold grade to the lowest 8K grade, knowing the traits between the different grades separate professional from amateur gold appraisers.
The color of gold is a direct reflection of how much gold is contained within the object. Because metals such as silver, nickel, copper and zinc are mixed with lesser karatage golds, it will make the 8K, 14K and 18K gold objects seem more of a duller-yellow tint than 24K gold. If the color is a deeper tint of yellow, there is more karat gold. A trained-eye professional can tell the difference while amateur gold appraisers may need a color chart to determine the karatage in the gold.
Touch and Feel
Pure gold is generally soft and easy to bend with your bare hands. Because lesser values of gold contain more common metals that are harder to bend such as nickel and silver, a 14K gold piece of jewelry will be harder to melt and manipulate than a 24K gold piece.
Gold Testing Kit
Gold testing kits are available to examine your gold piece and determine the karat grade. Each kit will include a test needle, testing solution and testing stone. The testing needle will be labeled with the karat grade and will include a small trace of gold. Take the 8K, 14K, 18K or 24K testing needle and scratch it on the testing stone. Scratch the piece of gold piece you are testing on the stone as well. Apply some testing solution to the stone and the chemical will react with the gold deposits to show a certain color. Your testing kit will include a color chart in which you can compare the purity and gold grade of your piece.
Read the Label
If you are purchasing a piece of jewelry with genuine gold, a small label indicating the karat grade may be engraved into the piece. Although you may need a magnifying glass and bright light to be able to see the label, this could be the easiest way to tell the difference between the grades of gold.