(Fun fact: Real gold is not magnetic.) Fake gold, on the other hand, will stick to the magnet.
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.
Check if your gold is real by performing the magnet test. Real gold will not attract a magnet. To test if 18k gold is real, hold it next to a magnet. If the magnet sticks to your jewelry, then it does not have a high percentage of gold but is made up of other, more magnetic metals.
Gold (Au) in its bulk form, like the metal in a wedding ring, is not considered a magnetic material. Technically, it is classified as “diamagnetic”, meaning that it can be repelled by a magnetic field, but cannot form a permanent magnet.
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.
On the other hand, a piece may be gold plated, but it will not attach to a magnet because its core metal is non-magnetic.
Place your jewelry on a table or hold it in your hand, pour some white vinegar on the metal directly (a dropper can also be used) if the metal of the jewelry changes its color, it is not pure gold and if it keeps shining then you have real gold in your hand.
To conduct the test, get a dark surface like a black stone. Rub your gold jewelry on it until it leaves a visible mark. Apply a few drops of nitric acid to the mark. It will dissolve any metal that's not gold, so it should basically clear out the mark.
Fool's gold is actually iron sulfide, a non-magnetic, inexpensive and abundant material that is a byproduct of petroleum production.
Natural Diamonds are magnetically inert (diamagnetic). They can be imitated by natural Zircon, and by many man-made materials such as Moissanite, Strontium Titanate and synthetic Rutile (all diamagnetic).
Pyrite, also known as fool's gold, is magnetic, while gold is not. By using a magnet, you can quickly and easily tell the difference between the two. You can apply this simple test to anything in your home that you want to test for pure gold.
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.
It indicates that the material's composition is 92.5% silver and 7.5% copper. This means it's both fairly malleable and bright. However, some people assume that when a piece of gold jewelry features this hallmark, it means the piece has a gold content of 92.5%. This is not the case.
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.
Most other letter markings indicate that a piece is gold-plated or gold-filled. Gold-plated pieces may be marked 'GP,' 'GE,' or 'HGE. ' 'GP' or 'GE' means the piece is electroplated with a thin layer of gold; '18K GP' would indicate a piece plated with 18 karat gold.
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.
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.