Natural pearls come from oysters and other mollusks in the sea and are quite valuable. Cultured or freshwater pearls come from pearl farms, which create pearls by implanting a tiny bead in a mollusc. A beautiful substance called nacre then forms around this bead. Fake pearls are made of glass, plastic and other materials. When buying pearls, terms that indicate fake pearls are imitation, faux, simulated and artificial. There are tests you can perform to determine if pearls are real or fake, but the only sure way to truly verify their authenticity is to have them checked by a certified gemologist.
Look at the pearls in the sun or a very bright light. Real pearls have a body colour and an overtone colour. They reflect light and have a natural lustre. Fake pearls have one flat colour with no depth.
Check the size and shape of the pearls. With real pearls, there are slight differences in the shape and size of each pearl. Fake pearls look perfectly round and exactly the same size as all the others in the strand.
Examine the pearls with a magnifying glass or jeweller's loupe. Check the pearls for tiny imperfections. You should see ridges, irregularities and tiny flaws in real pearls. Real pearls look scaly and fake pearls look grainy.
Inspect the drill holes. Real pearls have smaller drill holes and are smoother at the edges around the holes. Fake pearls have larger holes and rough edges.
Perform the tooth test. Rub the pearls against your teeth. If the pearls are rough, they may be real. Genuine pearls have layers of nacre with irregularities that can feel gritty or bumpy against the teeth. Fake pearls are perfectly smooth. This seems simple, but don't base your assessment on this test only. The tooth test is not always accurate. With real dyed pearls, the dye fills in the depressions, making them feel smooth.
Examine the setting or clasp of the pearls. If it is a genuine pearl ring, the setting will be gold, white gold, sterling silver or platinum and will be marked as such. The clasp of a strand of real pearls will also be high quality and marked. Also, there is a knot between each pearl in a strand of real pearls.
Have a certified gemologist X-ray the pearls if you want to be absolutely certain they are real. An X-ray shows the inside of the pearl, variations in its density and shape of the drill holes.
Treat your real pearl jewellery with care. Apply cosmetics, perfume, lotion, sunscreen and hairspray before putting on your pearls. Wipe your pearls with a soft, damp cloth if they need cleaning. If they are very dirty, get them cleaned professionally.