Check the signals. Protect the pearl.

Start with a group of clues, not one trick

No single home test reliably separates every cultured, natural, treated and imitation pearl. The useful approach is to combine non-destructive observations: surface variation, lustre, drill-hole detail, weight, temperature, matching and the quality of the mounting. A suspicious result means “inspect further,” not automatic proof.

Should you rub a pearl against your teeth?

We do not recommend it. The test is unhygienic, subjective and not conclusive, and it encourages people to treat a delicate surface casually. Gentle magnification and good side lighting reveal more useful information without putting the pearl in your mouth or scraping the nacre.

Are perfectly round pearls fake?

No. Fine cultured pearls can be round and beautifully matched. Extreme uniformity may be one clue in a low-priced strand, but it must be considered alongside lustre, surface, drill holes, weight and seller documentation. High-quality matching is itself valuable.

What a screen cannot prove

Visual inspection cannot reliably prove natural origin, identify every treatment or see the internal growth structure. Gem laboratories use methods such as radiography, microscopy and spectroscopy when the distinction matters. The checklist deliberately stops before destructive folklore such as burning, cutting, chemical tests or forceful scratching.

When to take the pearl to a professional

Seek a jeweller or laboratory when the item is valuable, inherited, represented as natural, sold with an important origin claim or shows damage around a drill hole or setting. Keep receipts and reports, and ask exactly what conclusion the document supports: identity, treatment, mollusc type and geographic origin are different questions.