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.
Gold nuggets cannot be tested with apple cider vinegar as they may contain other metals. The naturally occurring alloys may give inconsistent results depending on the purity of the nugget.
How to Test Gold With Vinegar. Apply a few drops of white vinegar to your gold jewelry. Real gold will not change color, but vinegar can cause fake gold items to react and change color.
Test With Nitric Acid
Make a mark deep enough to scratch through the top layer of gold. Carefully apply a drop of nitric acid to the mark, and determine if the mark turns green or milky. There will be no reaction if the jewelry is either gold or mostly gold.
Vinegar Test
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 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 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.
The short answer is yes, ACV can clean the grease and dirt from your jewelry. It can also revive the tarnished silver pieces. However, ACV is not the right medium if you are looking for the luster associated with professional chemical cleaning.
The purer the gold, the stronger the acid required to dissolve it. Measured strengths of nitric acid are used to test for 14k and lower. 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.
Cleaning your gold and gemstone jewelry couldn't be easier with white vinegar. Simply drop the jewelry into a jar of vinegar and let sit for 10 to15 minutes, agitating occasionally. Remove and scrub with a soft-bristled toothbrush, if necessary.
One of the simplest tests that can be conducted to determine if your gold is real is to drop it in a bowl of water. Gold is a heavy metal, so if the object has a high purity level, it should sink to the bottom with ease. If it floats, it's probably fake.
Rub your gold against a jeweler's stone.
Wipe it across the stone firmly enough to leave a mark. If the mark that you've left on the stone is solid and gold in color, then the piece is pure. If there is no line or only a faint one, then the piece is likely plated or not gold at all.
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.
Scratch test.
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.
Finally, we suggest both for silver and gold plated items, not to use abrasive substances such as lemon, vinegar, salt, parmesan, cola, because they tend to corrode the surfaces.
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.
Heat your gold jewelry with the lighter.
Once everything is ready, begin the test. 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.