Look for a hallmark stamp such as 10K, 14K, 18K, 22K, 24K, or 999
Check for discoloration, especially where the item rubs or wears
Use a magnet; real gold is not magnetic
Compare the weight; real gold feels heavy for its size
Rub it on unglazed ceramic; real gold leaves a gold streak, not black
Test with nitric acid or a gold testing kit
Check for skin staining or green marks after wearing
Inspect for signs of plating, such as worn edges showing another metal underneath
Have it tested by a jeweler or pawn shop with professional equipment
Use an electronic gold tester or XRF analyzer for accurate results