Check for hallmarks or stamps such as 10K, 14K, 18K, 22K, 24K, or 999
Look for discoloration, especially where the item is worn or scratched
Use a magnet; real gold is not magnetic
Weigh the item and compare it to known gold pieces of similar size
Perform a ceramic scratch test on an unglazed surface
Try a nitric acid test using a gold testing kit
Use a density test by measuring weight and volume
Inspect for skin staining or fading over time
Test with an electronic gold tester
Have a jeweler or appraiser verify it professionally