The perspiration from your hands will either react with the metal and change the color of your skin or leave it unaffected. When real gold is in direct contact with your skin there is no discoloration. If the gold is fake it will cause your skin to turn black, blue, or green at the contact points.
Genuine gold will stand up to your attempt to conduct a nitric acid test at home. Make a tiny mark on the piece of gold to penetrate the surface. 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 is a very soft metal, so scratching it with a hard object like ceramic will leave a golden or a yellowish streak. On the other hand, fake gold is often made of metals that are darker in color, so you'll see a dark streak instead.
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.
Out of all of the options, gold plated pieces are the most affordable. However, because there is a thin layer of gold applied to a base metal, gold plating over time will wear away or can flake off.
The most common mineral mistaken for gold is pyrite. Chalcopyrite may also appear gold-like, and weathered mica can mimic gold as well. Compared to actual gold, these minerals will flake, powder, or crumble when poked with a metal point, whereas gold will gouge or indent like soft lead.
On average, gold plated jewelry can last about two years before the gold plating begins to tarnish and wear down. However, the length of time can be much shorter or longer depending on whether or not you decide to properly maintain your jewelry collection.
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.
Hidden copper inside metal jewelry is the most common reason your skin turns green. Costume jewelry labeled as being made of nickel and even pieces that are silver- or gold-plated often contain copper or copper alloys (a blend of metals that has copper as a component).
Real gold sinks in 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.
A float test using water is the easiest and safest way to tell if your gold is real at home. Start the process by taking a glass and filling it with water. Drop the gold accessory you want to test in the filled glass. If your gold piece sinks to the bottom of the glass, it is real.
On the contrary, if the piece of gold is fake, it is often made of lighter metals, so it will either float or be slower to sink. Similar to the magnet test, this test isn't always dependable. Some pieces of gold that are fake are heavy and dense like real gold, so it will sink to the bottom.
The Ceramic Scratch Test
Take an unglazed ceramic plate or piece of tile and scrape a piece of gold across its surface. Real gold will leave a gold mark or trail. Other metals will leave a black trail.
Fool's gold is the most common of these. Better known as Iron Pyrite, this sulphide mineral is infamous for looking just close enough to gold to fool the untrained eye. Fool's gold is much less dense than the real thing however, so this is a very easy way to check between the two.
Drop your gold piece into the filled container. Gold will sink quickly, while floating or moving very slowly means you likely have fake gold on your hands. This is also true if the item floats. Tarnishing and rust after being in water is also a sign of fake gold.
Gold is a very soft metal. When scratched across a ceramic surface, gold will leave behind a streak of gold. However, brass is harder and will leave a black streak on the same surface. Simply press the metal to an unpolished ceramic surface and pull it across the surface.
"Fool's gold" is a common nickname for pyrite. Pyrite received that nickname because it is worth virtually nothing, but has an appearance that "fools" people into believing that it is gold. With a little practice, there are many easy tests that anyone can use to quickly tell the difference between pyrite and gold.
Pure gold (24K or 999) has a rich, nearly orange-yellow colour, however gold rarely occurs in nature in pure form. It generally grows as a crystal structure including other elements, like silver or copper.
In conclusion, it is not advisable to wear 18K gold-plated jewelry in the shower or while swimming. Exposure to water, soap, shampoo, hot water, steam, moisture, and humidity can pose risks of damage to the delicate gold plating.
Showering with gold-plated jewelry is not recommended, as the constant exposure to water and moisture can cause the gold plating to wear off quickly. Gold plating is a thin layer of gold applied to a base metal, and frequent exposure to water can cause it to deteriorate, exposing the base metal underneath.