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.
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.
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 desired result is a clear drop of liquid that does not change color.
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.
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.
The average lifespan of gold-plated pieces is two years. After that, the gold plated jewelry tarnishes and starts to wear down. Depending on how well you maintain your jewelry collection, this period can vary. You can take the jewelry to a jeweler to have it re-plated if it starts to lose its gold plating.
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.
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.
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.
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. The brighter your jewelry gets, you can rest assured you have real gold.
If the hallmark is absent, this could mean the jewelry does not contain real gold. However, there are other possible explanations. It is possible the hallmark has worn away over time, which can happen if the item is in constant contact with skin.
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.
More commonly counterfeited gold coins are Chinese gold pandas, $20 Liberty Head gold coins and St. Gaudens gold coins.
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.
It's generally not recommended to wear any type of gold-plated jewelry, including 18k gold-plated jewelry, in the shower or while swimming.
While Jewellery with Gold Plating can look just as stunning as solid gold jewelry, one of its main cons is that it can be more prone to wear and tear. This is because the thin layer covering the base metal can easily scratch or chip off with frequent wear, exposing the less appealing metal beneath.
The green color is from a chemical reaction called oxidation between the copper metal and things like water or chemicals. The same reaction can happen with your jewelry. Some jewelry is made of copper, with silver or gold on top.
It doesn't react with oxygen, so it never rusts or corrodes. Gold is unaffected by air, water, alkalis and all acids except aqua regia (a mixture of hydrochloric acid and nitric acid) which can dissolve gold. In fact, gold's acid resistance is one of the reasons why our acid assays are so accurate.
Under normal conditions, gold should not change color. However, due to use and time, it may get scratched and tarnished which can damage the cosmetic look of the gold.
2. Why does the gold turns black? Gold turns black when some base metals alloyed with the gold react with or even to oxygen it can eventually discolor or even tarnish your gold jewelry. This Oxidation is working as a chemical reaction in which the electrons are lost.