Gold mining

How do you tell if gold is real, gold plated, or fake? By most international standards, anything with less than 41.7% or 10 karats of gold is considered fake. To test your jewelry or gold at home, you can perform a few easy tests–mostly with items you already have, like water, vinegar, and magnets. You don’t have to be a certified jeweler to get a good idea of whether or not your gold is real, and we’ll give you step-by-step instructions to test your gold right now.
1
Drop the gold into a jug of water to see if it sinks. Get a container big enough to hold both the water and the gold you’d like to test. The water temperature you use doesn’t really matter, so lukewarm water is fine. Real gold is a dense metal, so it falls directly to the bottom of the jug. Imitation gold is much lighter and floats.[1]
Real gold also doesn’t rust or tarnish when wet, so if you see a discoloration, you probably have plated gold.
2
Put a few drops of vinegar on the gold. Set your jewelry or gold piece onto a flat surface. Use an eyedropper to apply a bit of vinegar and let it sit for about 15 minutes. Real gold won’t change color, but fake gold will.[2]
You can also submerge the gold in a glass container with vinegar for 15 minutes. This is a slightly riskier method because vinegar might damage semi-precious stones on gold jewelry.
3
Find any noticeable discolorations where the gold has worn away. Gold is pretty soft for a metal, so plated gold often rubs away over time. The best places to check are around the edges of jewelry and coins. These spots often rub up against your skin and clothing throughout the day. If you see a different metal underneath the gold, you know your item is plated and not considered real gold.[3]
For example, a silver coloring might indicate silver or titanium. A red coloring could mean copper or brass.

Note any discolorations on your skin from wearing or holding the gold. Pure gold doesn’t react with sweat or oil from your skin, so if you see black or green marks, they are from other metals. Silver leaves behind black marks and copper leaves behind green marks. If you see a lot of these marks on your skin, your gold may be less pure than you expect.[4]
Keep in mind that most gold items are blends of gold and other metals. Even something like a 14K piece of jewelry, 58.3% gold, can leave these marks. Use other tests as well to ensure your gold is authentic.