Identifying whether jewellery is 24-carat gold is quite simple, as this is the purest form of gold. Aside from the standards used by professionals all across the globe, there are a few tricks that will tell whether the jewellery is the real deal or if it's fake. It's easy to identify fake jewellery as it will tarnish and turn skin green, but this may take some time depending upon the care the jewellery receives.
Go to the local hardware store to purchase a piece of unglazed porcelain tile. Rub the piece of 24-carat gold jewellery across the unglazed porcelain tile. If the mark appears gold, then the jewellery is pure, or real. If the mark appears black, the jewellery is counterfeit.
Weigh the piece of jewellery. If the piece is truly 24-carat gold, it will have a low weight. The measurement system of jewellery is very different than that of the normal metric system. One gram of pure, or 24-carat gold, will weigh 0.643 dwt; dwt is the standard pennyweight measurement of gold.
Measure the density of the jewellery. The Moh's system measures jewellery using a scale of hardness. Gold jewellery measures around 2.5 to 3 on the Moh's scale, depending upon the carat and other precious metals that may be found in a specific piece of gold such as alloy or aluminium; glass has a hardness of 5.5. The way to test the hardness of your jewellery is by scratching or cutting a piece of glass with the item in question. If the jewellery cuts the glass, it is not real because it's harder than glass.
Hold a magnet near the piece of jewellery in question. If it's truly 24-carat gold, the magnet will have no effect on the jewellery. If the magnet attracts the jewellery, it is not pure 24-carat gold. The magnetic attraction does not necessarily mean the piece is fake. The magnetic attraction simply proves there are a significant amount of other metals mixed in the jewellery.