One of its numerous imitations is called 'Amberdan'. It has properties fairly near to natural gem. The way to test the originality is when the stone is heated and gives off a certain odor. When the odor smells like a mixture of plastic and amber, it suggests that a natural resin has been mixed with a plastic binder.
Amber is often confused with copal. These two stones are composed of very similar materials with nearly identical origins and so it is difficult to identify the original amber. The main difference is that while copals are just a few hundred thousand years old, ambers are several million years old.
Another imitation that is found in the market is made up of pressed amber, or 'ambroid'. This is created by fusing smaller bits of the gem under heat. This can be distinguished from original gem when you examine it under a microscope.
Ancient techniques for identifying this gem are still useful today. When it is rubbed vigorously on a piece of wool, it generates a static charge, which is enough to pick up a small piece of ash. When this gemstone is warm enough, it tends to give off a distinctive odor. These techniques will separate it from plastic imitations but not distinguish it from copal.
To distinguish this gem from copal is difficult. They share the same refractive index, specific gravity, and most other properties. However, Copal tends to fluoresce whiter than amber under UV light. So, it is a judgment call which one needs to make based on having examined a sufficient number of samples so as to recognize the difference.
If one is not able to make the distinction based on fluorescence, then one will have to resort to a destructive test. On an inconspicuous area of the stone, place a drop of acetone. Let it sit for three seconds, and then wipe it off. Copal will have the surface damaged by the acetone, while amber will show little or no change from the brief exposure.
Another easy method to separate this gemstone from its plastic imitations is with a specific gravity solution. Boil water and add as much salt as you can dissolve in it to create a handy testing liquid. Most of the imitations will sink in this solution. This is because few plastics have a density as low as 1.05 and many can be lower than amber if they have air bubbles inside. So, if your sample sinks, you can be sure it is not real. If it floats you, need to determine if it is plastic or amber.
There is another destructive test to separate real amber from the fake ones. However, it must be done with care. The best part is that it can be done almost invisibly. Find a place on the stone where a mark would be as unobtrusive as possible. This can be on the edge, bottom or on an area with scratches. Next, heat the tip of a needle until it glows red. Touch the selected spot just enough to release a tiny whiff of smoke. Now smell the smoke. If it is genuine amber, the smell is of fine incense. It is plastic if it is chemical and offensive. This is another reason to make your test on as small a scale as possible!
Another test of discovering a fake piece is to identify the insect inclusions present in the stone. If one finds this stone which has an inclusion of say, a modern house fly, this can easily alert you to the fact that the stone may be a fake. This is because the house fly did not exist millions of years ago, which means that the inclusion has been fused into the stone, and that the stone is not genuine.
With these tips and techniques, it thus becomes easier for you to identify and spot a genuine amber gemstone from among the fakes.