How Can You Tell If Pearls Are Real?

The first question about any pearl is whether it is a pearl at all, natural or cultured, or an imitation pearl. Some simple checks can point to an imitation, but each one has limits.

Look at the surface#

Real pearls are made of nacre, which under magnification shows overlapping platelets. Imitations lack them. GIA describes imitations as often showing a glittery surface from their coating material, and sometimes molded drill holes.² In one group of shell-bead imitations, magnification showed many tiny glittering particles instead of nacre platelets.³

A look that is too perfect can be a clue as well. In GIA’s study of Majorica imitations, strong iridescence on a smooth surface, together with a very high luster, pointed to an imitation; on cultured pearls, that kind of iridescence was more common on irregular surfaces. Most other imitations of the time, made by dipping or painting beads in resin, showed no iridescence at all.¹

Look at the drill hole#

The drill hole shows what is inside. Under 10× magnification, a cultured pearl shows a thin, often dark layer of conchiolin between the shell bead and the nacre, and the edges of the hole are sharp and well defined.¹ The imitations GIA examined had no such layer, and ragged edges.¹

Cultured pearl

• A thin dark layer between bead and nacre
• Sharp, clean edges at the hole

Imitation

• A bead with only a thin coating
• Ragged coating at the hole

Text version of this diagram

The drawing shows two beads cut through the drill hole. The cultured pearl has a shell bead in the middle, a thin dark ring around the bead, and rings of nacre outside it; the hole runs straight through with clean, straight edges. The imitation is a plain glass bead with only a thin colored coating on the outside; where the hole passes through the coating, the coating’s edges are drawn ragged.

Coatings can chip and peel near the hole. On some shell-bead imitations, the damage exposed the white shell underneath.³ An unusually large drill hole can be a warning sign too.²

The tooth test#

In GIA’s study, the tooth test was one of four conclusive tests: the cultured pearls felt gritty against the teeth and the imitations felt smooth.¹

The test has limits. Natural pearls share most surface characteristics with cultured pearls,¹ so the tooth test can’t tell them apart.

Weight and other quick checks#

Weight isn’t a reliable guide. GIA found coated shell-bead imitations similar in heft to cultured pearls.³

Avoid any test that damages a pearl. A dilute hydrochloric acid solution makes a cultured pearl effervesce,¹ and CIBJO says pearls should be kept away from all acids.⁴

What a laboratory can tell you#

A gem laboratory settles the question. In GIA’s study, the imitations had a significantly lower spot refractive index than cultured pearls, and on X-ray they appeared opaque, without the contrast between bead and nacre that a cultured pearl shows.¹

X-ray imaging also separates natural from cultured pearls: a natural pearl shows no bead or curved cavity at its center.⁵ Laboratory reports state whether a pearl is natural or cultured, and SSEF’s reports also indicate treatments.⁶

Imitations can still surprise a lab. In 2025, GIA’s Mumbai laboratory found one imitation among about 9,360 pearls in 18 strands.² It looked like the pearls around it, and its X-ray image even showed arcs like the growth arcs of the natural pearls beside it, but other tests showed it was not a pearl.² The page real vs imitation pearls explains what imitations are made of, and the “are my pearls real?” checklist takes you through the checks one by one.