The only way to know for certain that an object is made of gold is to have it analyzed. But a few do-it-yourself tests can provide enough information to make an educated guess.
: Wear rubber gloves and suitable eye protection when working with nitric acid.
Step 1: Test with a magnet Check whether the object is magnetic. Gold is not magnetic, so if the object is attracted to the magnet, it is not gold. But just because the object is not magnetic does not mean it is gold.
Step 2: Check the hardness Test the material's hardness with a steel file. Gold is soft, and bends easily, so if the material bounces back from the file; it is made of some other material.
TIP: File beneath the surface, as the object may be gold plated.
Step 3: Test with acid Put on your gloves and glasses and apply a drop of nitric acid to the file scratch. Then, rinse with running water. If there is no reaction in the metal, the material is gold; if the object turns green, the object is made of a base metal; and if it turns milky, the object is gold-plated silver.
Step 4: Take the object to a jewelry shop If all else fails, take the object to a jewelry shop and have it x-rayed.
FACT: The terms karat, spelled with a K, and carat, spelled with a C, are different. Karat with a K describes the purity of a substance and carat with a C is a measure of a gemstone's weight.