If you are wondering whether the gold you purchased or found at home is real, the surest way to know is to take it to a jeweler and have it examined. However, if you want to check it yourself, here is a list of tests you can perform to determine.

Examine the piece looking for any official writings or markings. If you find a hallmark (a mark impressed into the metal), it should indicate the purity of the gold, expressed in parts per thousand (1-999 or 0.1-0.999) or in karats (10k, 14k, 18k, 22k or 24k). Generally, gold items are no less than 9 karats (in America, anything less than 10k is considered fake gold) and always have a hallmark indicating the karat. Using a magnifying glass will make it easier to spot the hallmark, and if it is missing, the item may be fake. It is possible, especially on older items, that the hallmark may be illegible or have disappeared due to wear. Counterfeit items often have a hallmark that appears authentic. However, it may be necessary to conduct further testing.

Check for a noticeable color difference. It is important to check the surface color in the areas most exposed to friction (usually around the edges) as it is easy to see if the object is just gold-plated or solid gold.

• If the gold appears to be coming off and a different colored metallic surface is visible, the object is probably just covered in gold.

Who hasn't seen in the movies a gold prospector, a goldsmith or a bank clerk who bites a gold coin to check if it is real? We also see Olympic athletes biting their "gold" medals when they are handed over (whether this has any purpose is another matter).

Check your gold for marks. Ideally, real gold should have marks left by your teeth: the deeper the marks, the purer the gold.

• This is not a recommended method, mainly because: it can damage your teeth; it damages gold; there are metals, such as lead, that are even softer than gold and can make what could be, for example, just lead covered in gold, appear to be gold.

Hold a magnet close to the object. Gold is a diamagnetic metal (i.e. it does not react to magnetic fields), so if the object is attracted to the magnet it is fake. However, the fact that the object is not attracted to the magnet does not mean that the material is gold, as other diamagnetic metals are also used to counterfeit gold objects.

Density Test : There are very few metals denser than gold (and they are all very rare metals, some not even existing in nature). The density of pure 24k gold is about 19.32 g/cm ³ , which is much higher than most common metals. Measuring the density of your items can help you determine if your gold is real. Generally, the higher the density, the purer the gold. Remember that this test only works best if the item is made entirely of gold - gems or other decorations will affect the result. See the Warnings section below for more information on the density test.

Weigh your gold. You can ask a jeweler or goldsmith to do it for you (they usually do it for free) if you don't have a suitable scale. You will need the weight in grams.

Fill a test tube with water.

• If possible, use a test tube or container with a graduated scale, so that it will be much easier to take measurements for this test.
• The amount of water you use doesn't matter, as long as you don't fill the test tube to the brim: we have to immerse the gold in the water and the liquid level will necessarily have to rise.
• It is also important to remember to mark the water level before and after diving.