Gold, like many other precious metals, has unique properties that can be identified through examination or tests. You can learn to identify genuine solid gold and to tell it from the fake gold using a few simple tools at home.
We described a few other tests, like the acid test, the magnet test, and the hallmark test before. The density test is one of the more accurate ones and does not involve any damage to your piece of jewelry. You will only need scales that show the mass in grams, a cylinder, vial, or some other transparent container with volume markings on it (either milliliters or cubic centimeters is good), a piece of paper with a pen, and a calculator.
Step 1: Determine The Mass Of Your Piece Of Gold
Weigh your piece of gold on the scale. If you have a digital scale at home, that will do; or you can ask any jeweler to do it for you for free. Get your gold's mass in grams as accurately as possible and record it. Make sure it is indeed grams and not ounces.
Step 2: Determine The Volume Of Water In Your Vial
Choose a container that is voluminous enough to hold the gold. Fill it with pure water: tap water suits you just fine. If you don't have a graduated vial, you could try using a kitchen measuring cup. The amount of water does not matter as long as you have enough to submerge the gold fully. Leave some space the water does not spill over when we drop the gold into it. You want to have your container on the flat and even surface.
Check the water level: look at the markings on the cylinder, and record it.
Step 3: Determine The Volume Of Water After You Submerged Your Gold
Lower the gold into the vial, trying not to splash the water out or get it on your fingers (it would affect the measurement). You will notice that your water level rose: reread the markings to get the second measurement and record it as our New Water Level.
Step 4: Calculate The Density Of The Gold
Now we have three recorded numbers: the gold's mass in grams, the Initial Water Level, and the New Water Level.
Subtract the Initial Water Level (the smaller number) from the New Water Level. It will give us information on how much water in milliliters or cubic centimeters was displaced when we submerged the gold: this equals the volume of the gold piece itself. For example, if you started with 10 mL of water that rose to 12.5 mL, the difference will be 2.5 mL.
The gold's mass, divided by its volume, equals its density. Divide the gold's mass we had recorded by the volume we just calculated. For example, if you have a gold item that weighs 47.5 g and displaces 2 mL of water, you get a density of 19 g/mL (47.5 / 2.5 = 19).
Step 5: Determine If Your Gold Is Real
All you need to do now is to compare your number to the standard density of pure (24K) gold, which is around 19.3 g/mL. If your number is much lower, you likely have a fake or just gold coated.
The standard density would be slightly different if you have the gold of different karat: 14k yellow gold has a density between 12.9 and 13.6 g/mL; 14K white gold has a density of around 14.0 g/mL. 18K yellow gold density would be between 15.2 and 15.9 g/mL, while 18K white one has a density from 14.7 to 16.9 g/mL. Any 22K piece of gold has a density of around 17.7 to 17.8 g/mL.