There are ways to tell if your gold is real or counterfeit that most people can do in a simple and quick fashion. The simplest one that would let a person know if there is a possibility that your gold object might have a foreign metal in it would be the simple magnet test. By applying a real magnet as opposed to one from your refrigerator holding up a picture, to the gold object you should see no attraction. Gold along with copper and aluminum do not posses magnetic properties. Nickel, Iron and Cobalt along with all the ferrous metals and alloys made with them are magnetic. If the magnet is drawn to what you have hoped is gold, then the object is an alloy.
Most people have seen an old movie where a person is handed a gold coin and they bit it before accepting it. This is the oldest test for gold known to man. Gold is heavy and dense but not hard. A person can bit on a gold object and it will become easily dented. This test only applies to 24 karat to pure gold. 18k, 12k and the rest are just alloys with a percentage of gold in them. The metal used with them is generally harder and a person could hurt their teeth if they try to bite it.
Another simple test done at all pawn shops or gold dealers is the scratch test. This is done even when a stamp can be found on the object identifying it as gold. Stamps have been known to be fraudulent while the scratch test, while damaging, will determine within a few seconds if the object is solid metal or plated. The plating process is one of the most common manners in which fake gold jewelry is being attempted to be passed off as solid gold. By scratching the surface in an area that will not be noticed, look for discoloration or hardness changing in the metal. Gold is a very soft and dense metal. If the surface comes off to reveal another layer, you have a plated item. This is a good test for jewelry items. If you have gold bars, the process get a great deal more involved.
Gold bars and coins are thicker than most types of jewelry. Because of this the scratch test might not be sufficient to determine if it is plated or coated with gold. As recently as last year there were reports of counterfeit gold bars from China that were showing up on the New York City market which were hollowed out and filled with the metal tungsten. Tungsten was used because it is heavy enough to replace the gold so the shape and size of the gold bar would remain the same. This is where counterfeiters generally make the obvious mistakes. Gold bars are made in distinctive sizes and shapes. They are also marked according to their weight and the mint they come from. If what you have varies even slightly, then you more than likely have a fake in your hand.
Most counterfeiters know that most people do not pay that much attention to detail when making a purchase. In fact they count on it. This is why the plating process is done to conceal the crime they are attempting to commit. Since gold is twice as heavy as iron and considerably more than other metals like aluminum, to arrive at the same weight as a gold object, the item would have to become large and or thicker in size.
It is true that gold items are stamped with their purity on them, this can be faked and the reason for the above tests. With gold, never assume anything. Your best defense against purchasing or identifying fake gold is being observant. On chains each one has claps. If there is any discoloration at the joint then this is an indicator of another metal being present. This discoloration can also be in any other section where plating is uneven. Look at the object you have closely and in most instance you can identify fakes. Your eyes and knowledge about the type of gold item you are looking at is your best defense against being taken by a fraud.