Though it’s surprisingly low-tech, the quickest way is to rub two of the pearls in question together. If they’re real, they should feel grainy. You can also rub a pearl along your teeth and check for the same sensation of graininess. Fake pearls are typically very smooth. Their surfaces lack the grainy realism of the authentic item. If you need professional confirmation regarding a particular set of pearls, you could seek out the skills of a professional gemologist.

Best of luck…