One of the simplest methods for telling a fake gemstone from a real one is the microscope test. To perform this test, hold the stone up to a bright light and examine it with a 10x jeweler's loupe or a microscope. It is most likely a fake if the gem has any bubbles inside of it. This is primarily because when a fake jewel is made of glass, tiny round bubbles become trapped inside throughout the process, proving that the gem is actually fake.
The majority of tsavorites naturally contain imperceptible inclusions, such as needles, feathers, or crystal-like impurities (however, no bubbles). Therefore, if you can see them with a 10x jeweler's loupe, your stone is probably real.
The only person who can identify the difference between a genuine and fake tsavorite with perfect certainty is a professional jeweler. So, once you receive your gemstone, don't forget to have it examined by a gem specialist.