The easiest way to test gold at home is with a lighter, vinegar, a magnet, or an unglazed ceramic. All of these methods are safe and will give you a good indication of whether or not your gold is real.
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.
The Nitric Acid Test
Gold is a noble metal which means its resistant to corrosion, oxidation and acid. To perform this test, rub your gold on a black stone to leave a visible mark. Then apply nitric acid to the mark. The acid will dissolve any base metals that aren't real gold.
Gently drop your gold item into the 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.
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.
How to Do the Float Test to Check If Gold is Real. 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.
The Float Test
Place your gold piece into the water. If it's genuine gold, then it will immediately sink to the bottom of the cup. Pure gold is heavy due to its high density – 19.32 g/ ml. If your gold item floats or hovers above the cup's bottom – it's fake or plated gold.
Heat your gold jewelry with the lighter.
Apply the flame to the jewelry for about a minute or 60 seconds. Watch it closely for any changes in color. Fake gold will get darker, while pure gold will do the opposite: it will get brighter the hotter it gets.
Aqua regia, a mixture of one part nitric acid and three parts hydrochloric acid, is used to test higher karat purity through the process of comparison and elimination.
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.
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.
In conclusion, testing gold with alcohol is a simple and easy method that can be used to determine if an item is made of solid gold or if it is gold-plated. However, it is important to remember that this method is not as accurate as acid testing and should only be used as a preliminary test.
In their pure forms, gold and silver happen to be very soft metals—soft enough that you should be able to mark them with your teeth. According to the Mohs hardness scale—which relates pairs of materials according to which one will scratch the other first—gold scores a 2.5 and silver, which is harder, a 2.7.
Toothpaste can damage your diamonds, gemstones, gold and silver. Toothpaste is abrasive and has a hardness of around 3/4 on the Mohs Scale of Hardness. Metals such as gold and silver are softer, so toothpaste can actually scratch damage your gold and silver jewellery.
Float Test
It is one of the easiest ways of checking gold purity at home. If you put the gold jewellery in a bucket of water and it sinks, then it is made of pure gold. Pure gold is dense and therefore does not float while other metals would float or hover over water.
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.
Drop a small amount of liquid nitric acid on that scratch and wait for a chemical reaction. Fake gold will immediately turn green where the acid is. Gold-over-sterling silver will become milky in appearance. Gold will not react to the nitric acid.
Mix one part hydrochloric acid to 50 parts nitric acid and 12 parts distilled water.