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  • How to Tell if Gold Is Real
    • 1 Inspect high-friction areas for discoloration. If the item is plated, that's where the plating will begin to rub off. Discoloration proves that the gold is fake, but the absence of discoloration doesn't prove that the gold is real.
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    • 2 Hold a magnet up to the item. Gold is not magnetic, so if it sticks to or pulls toward the magnet, it's fake. If it doesn't react to the magnet, however, it could still be fake--just made from a non-magnetic material.
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    • 3 Test the density.
      • The density of gold is about 19.3 grams/mL, which is much higher than most other metals. Take the gold piece and weigh it. Then submerge it in a graduated vial of water and note the variation in volume. Divide your weight per volume variation (water level after gold submerged minus the water level before, in mL). Anything close to 19.3 grams/mL normally shows correct density, needless to say that you need a precise scale and vial for this method. Alternatively if you are measuring a solid for which the formula is known, you could use a caliper to determine its volume. Find the mass of the gold in grams, and then put some water in the graduated cylinder. It doesn't matter how much, but note of the amount in milliliters. Then put the gold inside the water (this won't damage it) and note the new water level. Get the difference between the two numbers in mL. Based on these two measurements (mass and volume), calculate using the formula: Density = mass/volume. If the answer is close to 19 grams/mL, then it is probably real gold, or a material close to the density of real gold, of which you can search for on the periodic table and use alternate tests to see if it is these metals instead. Remember your measurements will not be exact.
         
      • While it may be hard to measure the volume of a liquid displaced by a small piece of gold, here is an example calculation: Say a solid gold piece weighs in at 38 grams and then displaces 2ml of a liquid in a graduated cylinder of liquid. If you do the math, Density = Mass / Displacement - then 38g/2ml=19g/ml which is close to the density of gold.
         
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    • 4 Use the classic "plate." Use a piece of unglazed ceramic material. Rub the gold against it. Fool's gold will leave a black streak, and real gold will leave a golden streak.
       
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    • 5 Use Nitric Acid. You can also apply nitric acid to the item to see if it's real gold but nitric acid is hard to come by, and it's easier (and safer) to just have a jeweler do it. Gold is insoluble in nitric acid, which dissolves silver and base metals. This property is exploited in the gold refining technique known as "inquartation and parting". Nitric acid has long been used to confirm the presence of gold in items, and this is the origin of the colloquial term "acid test", referring to a gold standard test for genuine value.
       
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    • 6 A very rough way to check the density is to compare the item to one that's similar in size and that you know is real gold. They should feel equally heavy. If the item in question is noticeably lighter, it may very well be fake.