Pawn shops use various methods to test gold before pawning. One of the most widely used methods is the acid test, which involves applying nitric acid to the gold item to determine its purity. The magnet test is another simple method used to test if gold is real or not.
Nitric Acid is then applied to the mark. If it easily dissolves, the item is not Gold. If the mark remains, Aqua Regia (Nitric Acid and Hydrochloric Acid) is then applied. If mark is removed then this test proves the gold is genuine.
Stone (Hand Test) :
When soft metals like gold are drawn across it, they leave a visible line. The color of the line varies with the purity of gold. By observing the color on the line, an experienced jeweler can tell the purity of gold.
The most commonly used test is with nitric acid, which is a corrosive and colorless mineral acid. This acid reacts with many different materials, including copper-based alloys. When a piece of metal has a high concentration of copper, the reaction between it and the nitric acid is more powerful.
The Gold Acid Test is the most popular and accurate home gold test. This is because it may harm or damage only fake materials. However, make sure to perform the acid test only if your item was identified as non-magnetic during the previous test. This helps to avoid any unnecessary expenses and actions.
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.
Vinegar is very destructive, so when you apply the vinegar to a fake piece of gold, the vinegar will cause the jewelry to tarnish. Gold is a non-reactive metal, so real pieces of gold will not react to vinegar.
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. If that necklace leaps to the magnet, your significant other has some explaining to do.
The mark is tested by applying nitric acid, which dissolves the mark of any item that is not gold, stainless steel, zinc, tungsten, aluminum, platinum, or palladium. If the mark remains, it is tested by applying aqua regia (nitric acid and hydrochloric acid).
Make a small scratch on the gold and add a drop of bleach. If it changes color, your jewelry is not 100% pure 24K gold. Bleach can permanently damage gold jewelry. It can't tell you if your gold is fake, since most gold jewelry has other metals mixed in to give it strength.
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.
If you cut deep enough that you expose underlying metal, you can assume that it is plated. If it appears to be made of a uniform composition throughout, then it is probably solid gold.
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.
Once you have some vinegar, clean your piece of jewelry with a rag or cloth to remove any dirt so you don't get faulty results. Then, place your jewelry into a bowl and add a few drops of your vinegar into the bowl. Real gold will not change color, but fake gold will turn either black or green.
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.
While brass is not bright yellow, it's more dull than gold. However, gold is much shinier causing its golden color. Impurities can cause the shiny metallic luster that is characteristic of gold to fade. The purity of the gold determines the shine of ornaments.
Solid gold chains are made entirely from a gold alloy and will be stamped with a purity mark. Gold plated or gold filled chains, on the other hand, have a base metal like brass that has been covered in a thin layer of actual gold alloy.
Goldmeter - real gold detector on the App Store.
You can test to see if your gold is real by putting a little bit of vinegar onto it. Put your piece of gold on a flat surface or hold it in your hand. Carefully pour some vinegar onto the gold, or use a dropper to put a few drops onto it. If the gold changes color, then it is not pure gold.