Jewelers often use nitric acid to test their gold. Basically, gold won't react to nitric acid, but all other metals will turn greenish.
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.
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.
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.
If the gold is real, the mark or streak it produces should be golden or yellow color. A black streak means you have pyrite or another form of fake gold. You can also tell if gold jewelry is fake just by wearing it. Many types of fake gold will stain or discolor your skin after about 15 minutes of contact.
If the piece is real gold, the stamp should bear a manufacturer's mark and a karat marking, such as 14K or 24K. Fake gold may bear a karat mark, but will not have a manufacturer's mark.
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.
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.
In their pure, natural forms, gold, silver, aluminum, copper, brass, and lead are not magnetic. This is because they are all weak metals. Adding iron or steel to these metals can make them stronger and magnetic. Gold is often used in coins, jewelry, electronics, dentistry, aerospace, and awards.
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.
Goldmeter - real gold detector on the App Store.
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 must be stamped with a hallmark that tells the purchaser what karat the gold is. 18- karat gold will have a small stamp on the inside of the jewelry that reads 18k.
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.
Not sure if your gold is real or fake? It's simple: Solid gold never tarnishes, while faux gold—or gold-plated metal—does. If your jewelry has started to discolor and tarnish, or if it turns your skin blue or green where it comes in contact, then it's not solid gold.
Gold does tarnish and scratch over time. To preserve the luster of your gold jewelry, avoid exposure to household bleach and other cleaning products, which will quickly cause gold to discolor and possibly disintegrate.
SHINE: When you're viewing fool's gold with the natural eye, it will glisten, not shine. The edges will look sharp and it may separate in layers. Gold shines at any angle, not just when the “light is right”. HARDNESS: Get a piece of copper and try to scratch the copper with the gold.
More commonly counterfeited gold coins are Chinese gold pandas, $20 Liberty Head gold coins and St. Gaudens gold coins.
Yes, it can. Even while 18k gold is of greater quality than 14k or 10k gold, it can oxidize and become discolored with time. Take precautions to shield your gold jewelry from the elements and clean your pieces frequently to keep them looking their best for as long as possible.
Since 10k gold has a percentage of pure gold, 10k gold is worth anything that a professional jeweler deems valuable. Keep in mind though, the more wear and tear there is decreases the value of any real gold item.
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.