Real vs. Fake Pearls: The “Tooth Test” Is the Only Guide You Need, How to Instantly Tell a Real Pearl from a Cheap Plastic Bead.

You can tell a real pearl from a cheap fake in seconds using your teeth. It sounds strange, but it works because real pearls and imitations feel completely different against enamel. The “tooth test” is fast, safe when done gently, and accurate enough to sort genuine nacre from plastic beads on the spot. Here’s how to do it right, why it works, what to watch for, and a few instant backup checks if you want even more certainty.

Why the tooth test works

Real pearls are made of nacre. Nacre is thousands of layers of tiny mineral plates (aragonite) with organic glue (conchiolin) between them. Those layers are not perfectly flat. They create a microscopic, natural texture.

Plastic and many coated fakes are different. They are cast or coated to be very smooth. Smooth surfaces slide on enamel. Textured surfaces catch and vibrate a bit.

When you gently rub a pearl against the edge of your front teeth, you’re feeling surface texture. Real nacre feels a little gritty or like very fine sandpaper because of its layered structure. Plastic feels slippery and glassy. That contrast is what makes the test so useful.

How to do the tooth test correctly

• Clean the pearl. Wipe it with a soft, dry cloth. Dirt can mimic grit.
• Dry both surfaces. Moisture adds slip and can hide texture.
• Use the tooth edge. Lightly place the pearl against the biting edge of your front tooth (an incisor). Do not bite down.
• Gently rub side to side. A few millimeters is enough. You want surface feedback, not pressure.
• Test more than one pearl. If it’s a strand, try a couple spaced apart. That avoids judging by one damaged bead.
• Rinse your mouth and wipe the pearl after. Nacre dust is harmless, but cleaning is good practice.

Read your results

• Feels gritty, like fine sandpaper: Very strong sign of real nacre. You may notice a faint chalky drag. That’s tiny nacre particles breaking off, which is normal.
• Feels smooth and glassy: Likely plastic or glass. These slide with almost no vibration or drag.
• Feels mostly smooth with a slight tacky drag: Could be a coated imitation, such as “shell pearl” (a thick coating over a bead). Some coatings add a faint drag but lack true grit. Check the drill hole and surface closely to confirm.

Why this is reliable: you’re not guessing by look or weight. You’re measuring surface texture, which is hard to fake. Even high-quality cultured pearls have that micro-texture because they are layered nacre through and through.

Instant backup checks (30 seconds each)

Use these if you want to double-confirm in the moment. Each one has a reason behind it.

• Drill hole check. Real pearls: the hole edge looks sharp and the inside looks crystalline or “chalky,” not like paint. Fakes: coating often pools at the hole, looks glassy, or shows a clear boundary between coating and core.
• Luster and depth. Real pearls show a sharp reflection with depth—like light floating in layers. Plastic looks flat, with a smeared reflection. This happens because nacre’s platelets bounce light in complex ways.
• Weight and temperature. Plastic is very light and warms to your skin fast. Glass is heavy and feels cold at first. Real pearls sit in the middle: not too light, a gentle coolness that warms slowly.
• Rub two pearls together. Gently rub two against each other. Real pearls feel slightly abrasive and may leave a tiny nacre dust. Fakes glide smoothly or squeak without leaving powder.
• Surface under magnification. With a 10x loupe, real nacre shows minute irregularities and soft grain. Coated beads often show uniform, orange-peel texture, bubbles, or flakes near the hole.

Common traps and how to avoid them

• Very fine pearls can feel less gritty. High-quality Akoya or very thickly coated South Sea pearls may feel smoother. You should still feel a micro-drag, not glassiness. Compare multiple pearls on the strand.
• Old pearls worn smooth. Decades of wear can polish the high points. Test a protected area near the drill hole or a less-exposed pearl on the strand.
• Coated “shell pearls.” These are mother-of-pearl powder in resin on a bead. They may have a slight drag but lack true grit and depth at the drill hole. The coating can look too perfect and uniform.
• Dental work can confuse feel. Porcelain veneers and some composites are slicker. If your teeth are very smooth, use the two-pearl rub method or a loupe check as confirmation.
• Dirt and hand lotion. Residue adds false grit or slip. Clean and dry before testing.
• Do not scratch with a pin or knife. That damages pearls and still won’t reliably identify well-made imitations.

Real examples you can expect

• Thrift store “pearls” that feel slippery: Almost always plastic. Drill holes look melted or rounded, and the beads are very light.
• Vintage strand from a relative, gritty feel: Likely cultured freshwater or Akoya. Holes look crisp, luster is sharp with soft color overtones.
• Large, heavy, glassy-smooth “pearls” with perfect uniformity: Often glass beads with pearlescent coating. Cold at first, heavy for size, and the coating at the hole looks like paint.
• Big “South Sea” look with slight drag but no true grit: Often shell pearls. Check hole edges and the too-even surface pattern to confirm.

Care after testing

• Wipe the pearls. Use a soft cloth to remove nacre dust and skin oils. Oils dull luster over time.
• Avoid toothpaste or chemicals. They are abrasive and can etch nacre.
• Store properly. Keep pearls in a soft pouch, away from other jewelry that can scratch them. Pearls are softer than most gems.

What the tooth test can and cannot tell you

• It can tell: Real nacre versus plastic or glass. This is the fast, practical decision most people need.
• It cannot tell: Natural versus cultured, saltwater versus freshwater, or whether a pearl is dyed or bleached. Those require tools or lab work.

Why this matters: If you’re deciding whether a strand is genuine pearl or costume, the tooth test is enough. If you’re valuing an expensive piece, you need more than “real or fake.”

When to seek a professional opinion

If the pearls are likely valuable—fine luster, thick nacre, matching size and color, branded clasp—or you need to know natural versus cultured, get a professional appraisal. Jewelers can inspect drill holes, measure nacre thickness, and spot treatments. Laboratories can X-ray to reveal internal structure. The tooth test gets you to “real or imitation” fast, but lab results settle the fine print.

Bottom line

Do the tooth test first. Clean, dry, and gently rub on the edge of your front tooth. Gritty means real nacre. Glassy-smooth means imitation. If you want extra certainty, check the drill hole, luster depth, weight, and the two-pearl rub. Those take seconds and back up what your teeth already told you. You’ll avoid most fakes and know when it’s worth taking the next step.