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I am thinking of buying gold. If necessary, one gram at a time.

Is there a surefire way of checking if the alleged gold is real and of the stated caratage without a lab?

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    $\begingroup$ Buy from a trustworthy vendor. $\endgroup$ – Jeff Sep 6 '15 at 16:06
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    $\begingroup$ I can't believe no one mentioned Archimedes. $\endgroup$ – Pritt Balagopal Jun 22 '17 at 5:55
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There are lots of test for detection of real gold.

  1. Visual inspection: Inspect the piece for official markings. And look for noticeable discoloration. If the gold seems to be wearing off and showing a different metal beneath it, you probably have a piece that is only gold plated.

  2. Bite test: Bite down on your gold with moderate pressure. Examine your gold for any markings. In theory, real gold will show indents from your teeth; deeper markings indicate purer gold. This is actually not a recommended test, as you can damage your teeth.

  3. Magnet test: Hold a magnet up to the item. Gold is not a magnetic metal, so if it pulls towards, or sticks to the magnet, it’s fake.

  4. Density test: Weigh your piece of gold. Fill a vial with water. It’s helpful if the vial has millimeter markings on the side, since that will make it easier for you to read the measurements for this test. Place your gold in the vial. Use the following formula to calculate density: Density = mass/volume displacement. A result close to 19 g/ml indicates either real gold, or a material with a density similar to gold. 

  5. Ceramic test: Find an unglazed ceramic plate to use. Drag your item across the surface. A black streak means your gold is not real, whereas a gold streak indicates your item is genuine.

  6. Nitric acid test: Place your piece of gold in a small stainless steel container. Put a drop of nitric acid on your gold and watch for any resulting reaction to the acid. A green reaction indicates your item is either a base metal or gold plated. A gold reaction indicates your item is gold-plated brass. A milk-colored reaction would indicate gold-plated sterling silver. If there is no reaction, you mostly likely are dealing with real gold.

Click here for detailed steps.

Try to perform all or at least 4 steps to confirm (with ceramic test compulsory).

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  • $\begingroup$ This is an excellent answer but a Google search away. Can a fake alloy fool some or all of these tests? $\endgroup$ – JJ_Jason Sep 6 '15 at 13:28
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    $\begingroup$ @JJ_Jason density test, ceramic test and nitric acid test cannot be fooled by a fake alloy, according to me. $\endgroup$ – curiousbrain Sep 6 '15 at 13:45
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    $\begingroup$ Density is fooled with tungsten $\endgroup$ – Mithoron Sep 6 '15 at 23:37
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    $\begingroup$ @Mithoron But tungsten is much more harder than gold. $\endgroup$ – curiousbrain Sep 7 '15 at 7:02
  • $\begingroup$ Color would be bigger problem, but it can be simply put inside bars. $\endgroup$ – Mithoron Sep 7 '15 at 13:06

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