- If you hold real pearls in your hand, they will be cool to the touch for several seconds before warming up. Genuine pearls tend to warm with contact to the skin much faster than glass pearls. Resin or plastic pearls tend to feel somewhat warm upon first contact.
- Rub the pearls lightly along the biting edge of your upper front teeth. If they feel slightly rough, sandy or gritty, it's likely they are cultured or natural pearls because of the layers of nacre that have formed over time. If they feel smooth or glassy, they are probably imitations. That's because the imitations are made by dipping a plastic or glass bead into some sort of paint, sometimes including iridescent fish scales.
- Take two pearls then lightly rub one against the other. If they feel gritty or sandy, they are real pearls. If they feel smooth, they are not real.
- Quality pearls will have a sharp contrast between the brightest area where direct light is hitting the pearls and the shaded area creating an illusion of a “ball within the pearl.” Check for luster by examining them under a fluorescent lamp and rolling them from side to side to examine uniform luster.
- Real pearls tend not to be perfect and may have bands in their nacre, bumps, ridges, or pits. They vary in size and shape from one to another.There are three pearl shapes including symmetrical, spherical, and baroque. The spherical is the rarest and most desirable.
- Real pearls tend to be drilled from both sides, to meet in the center. If you could see the cross section of the pearl, the hole may appear wider at the outside edge of the pearl than at the center (which can make stringing poorly-drilled pearls very challenging). One reason for this is because a bigger hole means less weight and lower value, since the weight of a pearl affects its price. The holes of fake pearls often form a shallow bowl shape while the holes of real pearls are more likely to be flat.
- Real pearls are heavier for their size than plastic, resin, or hollow glass pearls.
- In a finished pearl necklace or bracelet, real pearls are more likely to have knots between each pearl than fake pearls. Real pearls are more likely to have settings of gold, silver, or platinum than faux pearls.