Pure Pearls Glossary
Tooth Test
Rub a pearl gently against the edge of a tooth. Real nacre feels faintly gritty; an imitation feels glassy smooth.
The grittiness comes from the microscopic overlapping platelets of nacre. A coated glass or plastic bead has a continuous smooth surface.
It works reliably to separate real pearls from imitations, and it works in a shop in two seconds with no equipment.
What it cannot do is distinguish freshwater from saltwater, cultured from natural, or dyed from natural colour. All real pearls feel gritty.
What you will hear
“The tooth test proves a pearl is valuable.”
In fact: It proves the pearl is real. A very cheap potato pearl and an expensive round one feel identical, so it settles authenticity and nothing else.
When you are buying
Use the front edge of a tooth, not the flat, and rub lightly. Done gently this does not harm the pearl. Done hard it can scratch the nacre, so be light about it.
Read next
Imitation Pearl
A glass or plastic bead with a pearlescent coating. No nacre, no mollusc, no pearl.
Shell Pearl
A bead ground from shell and coated to look like a pearl. Not grown by a mollusc, so not a pearl.
Nacre
The material a pearl is made of: microscopic aragonite platelets glued in layers by conchiolin. Thickness determines both lustre and lifespan.
Cultured Pearl
A real pearl grown in a farmed mollusc after a technician places an irritant inside it. Essentially every pearl on the market is cultured.
Not sure what you are being sold?
Paste any pearl description — another shop’s listing, a message from a jeweller, an old certificate — and we will break it down term by term.