How could you tell if it is real gold?

Answer 1

There are various ways to test the authenticity of gold. Gold is denser than any other metal that might be slipped in as a substitute (osmium is denser, but it is also even more expensive) so if you measure its density you can generally tell. I will point out that since gold generally comes in irregular shapes (jewelry) rather than neat little ingots, you would measure the density by first using a graduated cylinder to measure the volume of the water that the purportedly golden object displaces, and then weigh it, after which it is a simple matter to divide weight by volume to get density. An advantage of this technique is that it doesn't just tell you if the surface is gold, it tells you if the entire object is gold, all the way through. Other tests don't do that.

Gold is also softer than other metals which are commonly used, which is why people used to sometimes bite coins to feel how soft they were (although this is not a very precise test). And if you suspect gold plating, you can of course try to scratch through the gold to see if there is another color of metal underneath.

Gold also is more inert than most other metals (and again, any other metal that is as inert as gold is also as expensive as gold, or more expensive, so it would not be used to counterfeit gold) so you could test a purportedly golden object by putting it into a beaker of sulfuric acid, and seeing if it reacts.

If you have access to a mass spectrometer, you can do a very precise test.

Answer 2

One way to determine if gold is real is by conducting a specific gravity test, which involves comparing the weight of the object in air to its weight in water. Additionally, the use of a jeweler's loupe to inspect for specific markings like karat stamps can help verify the authenticity of the gold. Consulting a professional jeweler or appraiser can provide further confirmation.