Look for Stamps or Hallmarks in Your Gold Jewelry Most real gold is stamped with a hallmark that indicates its purity, aka its karat. The karat is the unit used to measure the purity of gold. The higher the karat, the purer the gold. The most common karats you'll see are 10k, 14k, 18k, 22K, and 24k.
Because pure gold is denser than other metals, a gold item will sink quickly and directly to the bottom of a tub or bottle of water. Fake gold can float or fall more slowly. Real gold also won't rust or tarnish when exposed to water, while gold plated items can show discoloration.
Real gold is typically marked with a hallmark, which denotes the purity of the metal. Look for marks such as 10K, 14K, or 18K, which indicate the percentage of pure gold in the piece. Authentic gold also has significant density and weight, so if a piece feels lightweight or hollow, it could be fake.
Fill a cup or bowl with water and carefully drop your gold piece into it. If the gold is real, it will sink to the bottom of the cup. If it's fake, it will float to the top or hover in the middle of the cup.
Acid test.
An acid test can reveal the karat of solid gold jewelry, but it can also show whether jewelry is solid gold or gold-plated. With an acid test, a small sample of the jewelry is removed and exposed to acid to induce a color change. The resulting colors indicate which type of metal the jewelry is made of.
What to do: Hold the magnet up to the gold. If it's real gold it will not stick to the magnet. (Fun fact: Real gold is not magnetic.) Fake gold, on the other hand, will stick to the magnet.
Goldmeter - real gold detector on the App Store.
If your gold piece turns black or green when the vinegar is on it, or if it starts to smoke or fizzle at all when the vinegar touches it, it is most likely not real gold. If your gold piece does not change colors and does not fizzle or react to the vinegar in any way, it is probably real.
999” or “1.000” would be pure gold and thus the same as 24 karat. Nonetheless, if an item of jewelry does not have this stamp – it is not necessarily proof positive that the item is made from fake gold. This is particularly true of older items of jewelry. Another method how to tell real gold is with a nitric acid test.
Heat your gold jewelry with the lighter.
Fake gold will get darker, while pure gold will do the opposite: it will get brighter the hotter it gets. The brighter your jewelry gets, you can rest assured you have real gold.
Prepare a cup of water, gently drop your gold chain in the water. If your gold chain sinks straight to the bottom of the cup, it should be authentic gold because real gold is denser than water. If your gold chain floats, it is not a real gold chain.
Since gold is both paramagnetic and diamagnetic, both cancel one another out and become weak. So a strong magnet will attract gold ever so slightly and will also repel it.
Pure gold on its own cannot stick to a magnet. However, if you have an alloy of gold, then it could stick to a magnet. An example of a gold alloy that may stick to a magnet is gold with over 20% of its atoms replaced by iron. In very cold temperatures this alloy of gold may magnetize all on its own.
Scratch Test
If the metal doesn't change throughout the cut, the jewelry is more than likely solid gold. Gold plated jewelry will typically have a line of demarcation in the scratched area where the gold plating ends, and the base metal begins.
The apple cider vinegar gold test is a great choice if you want to test your jewelry at home, as it is readily available and easy to do. After all, real gold will not react when exposed to the acids in vinegar, toothpaste and more.
An excellent way to distinguish brass from gold is to use the acid test. Put one to two drops of nitric acid on the product you want to test. If there is no reaction, the product is gold. If you see a green, smoky, and fizzy reaction, there is likely copper in the gold you are testing.
Lemon Juice
Lemon is naturally acidic, which helps remove the oxide layer on the jewelry easily. Mix equal parts of water and lemon juice. Soak the jewelry in this solution for 10 to 15 minutes. Gently scrub the jewelry with a rough cloth or toothbrush.
Drop the Item in Water
Real gold is a heavy metal and will not float, so if your gold item floats you know it is not real gold. Also, if you notice rust or tarnishing on the item after being in water, this is also a sign it is not real gold since gold doesn't rust or tarnish.