Real pearls, either freshwater or cultivated, feel cold at first and then they adapt to body temperature. Imitation pearls always remain at room temperature and they are lighter, relatively speaking. When rubbing a real pearl against your teeth, you will experience a sand grain effect, because you are rubbing lime against lime. A false one, on the contrary, will feel very soft. Visually perforated real pearls will have a soft drilling rim, whereas such rim is more rounded on false pearls, as if the pearl melted away at the drilling.