Check gold coins & gold bars for authenticity

Also the sound propagation time ann be measured © Own image

All that glitters is not gold! Fake gold bars and gold coins are turning up again and again. As the counterfeits become more and more perfect, the difference between real and fake goods is becoming increasingly difficult to recognize, especially for laymen. Banks have in many cases already withdrawn from the detailed gold business after repeated bad purchases, and precious metal dealers have set up store - they have professional testing equipment and precise measuring methods at their disposal with which even the best gold forgeries can be identified. Some tests can be done with simple tools at home, and test whether your gold is really genuine.

You can check the authenticity of your gold yourself at home using the following methods:

Tip 1: Visual inspection

First, you should compare your gold coin or bar with the mint's official product images on the Internet or images in catalogs. Does the appearance of your gold piece correspond to the original or can deviations in detail be detected?

Some coins, such as the Vienna Philharmonic, are minted with the same motif in every year, other coins, for example the China Panda, look different in every edition. Pay special attention to the details and how they are worked.

  • Are the contours of the embossing clear or do they appear flattened?
  • Does the writing appear blurred or rubbed off?
  • Is the relief of the coin particularly high - or higher than the edge?
    (does the coin spin for a long time on a hard surface or does it brake quickly?)
Fluted edges © Own work

Also consider the edge of your coins and bars. Is the edge ridged or smooth, and should it really be? Can you detect any irregularities that indicate base metals have been incorporated?

If the edge appears rounded instead of straight - this could be a trick for counterfeit coins with less gold content to cover up some extra thickness to still inconspicuously match the weight of a real coin.

Cast ingots with visible solidification lines © Own work

In the case of ingots, unusual solidification lines and damaged edges can be indications of counterfeiting. Rounded or particularly polished areas on the sides of bars can also be a warning signal that foreign material has been incorporated. In the meantime, bars from some manufacturers already have embossed patterns to make subsequent manipulation more difficult.

Also check existing manufacturer's certificates carefully. It happens again and again that gold coins or gold bars are almost perfectly counterfeited, but the associated certificate or plastic blister is easily recognizable as a fake.

Check here the logos of the manufacturers or mints, printed texts and compare them with the official images of the cutting and minting companies.

Tip 2: Sound sample

Gold coins have a characteristic sound. If they are dropped from a low height onto a hard surface, they sound bright, persistent and "noble.

For laymen, however, this test only makes sense if you have at least two identical coins and can thus draw a comparison. If both coins are dropped one after the other, they should also sound similar.

This trick is very common and 99% of the time it is true, but it still happens that coins that are genuine sound fake due to production errors. If in doubt, just leave it alone.

Tip 3: Dimensions & Weight

More meaningful is the verification of measurements and weight. Because most base metals, such as copper, zinc, and lead, have a completely different density than gold, clumsy forgeries made of foreign materials can be noticed during measurement and weighing.

Check thickness with caliper © Own work

Use a fine weight scale and caliper (slide gauge) for checking.

For common investment gold coins there are also corresponding test templates, so-called coin fishes (e.g. "The Fish"), with which one can efficiently check diameter, thickness and weight.

First of all, it is necessary to check whether the diameter, shape and thickness of the bars and coins match the stated values of the issuing mints? Again, you can find the exact dimensions on the official websites, but also at specialized dealers (of course also here on Goldundco.at).

If your piece deviates from the indicated values, i.e. if the coin is significantly thicker or thinner, if your bar has completely different dimensions than it should have, the assumption is obvious that your piece is a fake.

Now place your coin or bar on the scale. Bullion coins and bars made of pure gold (999.9/1000 or 24 carat), with 1 ounce should then also weigh exactly 31.10 grams.

For coins with lower gold content, of course, this weight may differ. The 1 ounce Krugerrand (fineness 916.67 /1000 or 22 carats), for example, should weigh 33.93 grams because of the added copper of the alloy.

If the weight of your coin or bar - despite correct measurements - differs from the values of the original, it must be assumed that your piece is not genuine.

If your gold piece does not deviate or deviates only minimally from the nominal values, at least a clumsy forgery made of copper, brass & Co can be ruled out.

Tip 4: Check density with a water displacement test

Thanks to Archimedes' principle, we can check the density of our pieces. We make use of the fact that water (at 20° Celsius) has a density of 1 g/cm³ and the displaced quantity of water thus corresponds to the volume of the gold piece.

The first step is to weigh the coin or ingot to be tested with the precision balance (if you have not already done so). Then place a container of water on the balance and tare it to zero. Now dip the coin/bar to be tested by a thread into the water and get the volume of the piece in cm³.

Now divide weight (g) by volume (cm³) and obtain the specific gravity of the piece (g/cm³). Subsequently, the following table can be used to check whether this corresponds to the expected gold alloy:

Fineness Specific weight    Example
999,9 /1000
(24k)
19.3 g/cm³ Investment Bars, Vienna Philharmonic, Maple Leaf, China Panda
986 / 1000
(23,6k)
19.0 g/cm³ Ducats
916 / 1000
(22k)
17.82 g/cm³ Krugerrand, American Eagle, Sovereign
900 / 1000
(21,6k)
17.5 g/cm³ Guilder, Eagle & Double Eagle, Indian Head, Babenberger

More and more often, however, tungsten is used in gold counterfeiting, as this metal has an almost identical density to gold. Gold has a density of 19.32 g/cm³, while tungsten has a density of 19.3 g/cm³. Therefore, a tungsten core in a gold bar or a gold-plated tungsten coin is often not noticeable without further examination. However, a suspected tungsten fake can be checked for another property of real gold: Its magnetic properties.

However, misleading results can also occur if the bar or coin has air bubble inclusions or air bubbles stick to the relief when immersed in the water.

Tip 5: Magnetic properties

Even metals that are commonly considered "non-magnetic" react minimally to strong magnetic fields. While so-called diamagnetic metals are slightly repelled, paramagnetic metals are minimally attracted.

Gold - like silver, copper, zinc or lead - is diamagnetic. Tungsten, on the other hand, which is often used for gold forgeries, is paramagnetic.

To test the magnetic properties of your piece, all you need is a strong(!) magnet, a thread, and a coin case. Because the magnetic effect is only minial, we recommend the following "experimental setup":

Put your coin/bar into the coin case, and attach it to a long thread (you can also test blistered goods and attach the thread directly to the blister package.), and let this pendulum hang from the ceiling or a high table.

Once the "pendulum" is at rest, you can approach the coin or bar with the magnet. If the piece is slightly repelled, it behaves like gold, but if it is slightly attracted, the piece is not gold.

Platinum metals cannot be tested with this method because platinum and palladium are paramagnetic.

Professional test methods

As a professional precious metal dealer, we at Gold & Co have very accurate testing methods and can easily identify counterfeits.

In addition to the tests listed using magnetic scales, test templates and under the microscope, we subject questionable pieces to ultrasonic testing in our branches, which can not only identify admixtures of base metals, but also detect cavities (as can occur in bored-out bars).

X-ray fluorescence analysis (XRF) © Own work

We also use our equipment to test the electrical conductivity of a piece and can thus determine the authenticity of the coin alloy. X-ray fluorescence analysis (XRF) can also be used to find out the exact composition of an alloy. For this purpose, however, we also rely on proven acid tests- especially in the case of gold jewelry.

Conclusion

In general, it should be noted. There are no gold bargains that are significantly below the general gold price. If you are nevertheless offered gold at suspiciously low prices, there is certainly a catch! You should be especially careful when buying on the Internet. Most counterfeits in the field of gold investment products today come from China and enter circulation via online platforms such as Ebay or Alibaba.

PS: Bite test

We advise against the "bite test", i.e. biting into the gold coin, as we know it from movies and Olympic champions. If your piece is real gold, bite marks can actually appear in the soft metal and permanently damage the gold piece. Apart from the fact that there are other metals (lead, copper) that are even softer than gold, there is also the risk of damaging your teeth.

Play it safe with gold!

Sie sind sich nicht sicher, ob Ihr Gold echt ist oder möchten beim Goldkauf auf Nummer sicher gehen? Kommen Sie jetzt zu einem persönlichen, unverbindlichen und seriösen Beratungsgespräch in eine unserer Filialen in Wien 9, Wien 3 oder Wien 22.
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