How Can You Tell Whether a Gemstone Is Real?
It is THE question everyone asks before buying — or after inheriting a piece of jewellery: how can you tell whether a gemstone is real? Here is a dealer's honest answer: there are clues accessible to everyone... and only one truly reliable method.
Clues You Can Observe With the Naked Eye
- Inclusions: under a 10x loupe, a natural stone almost always reveals small inclusions — crystals, "feathers", colour zoning. A perfectly limpid stone at a gentle price should raise doubts;
- Round bubbles: perfectly regular spherical bubbles often betray glass;
- Coolness to the touch: a natural gem stays cold longer than glass or resin;
- A "too perfect" colour: a uniform, saturated hue without any zoning, at a low price, is suspicious.
Why These Tests Are Not Enough
The real modern challenge is not coloured glass: it is synthetic stones, chemically identical to natural ones, and undisclosed treatments. A synthetic sapphire has the same hardness, the same density and the same brilliance as a natural sapphire. To the naked eye — and even under a loupe for a non-specialist — the difference is invisible.
The Only Reliable Method: The Gemmologist and the Certificate
Only a gemmological laboratory, equipped with measuring instruments (refractometer, spectroscope, microscope), can formally authenticate a stone: its nature, whether it is natural or synthetic, and any treatments. That is the purpose of the gemmological certificate, issued by recognised laboratories. For a stone of any significant value, it is the only document that counts.
The Best Reflex: Traceability
The guarantee begins even before the certificate: knowing where the stone comes from and who is selling it to you. At Maxime Voillot Gems, we source our gems directly in the producing countries, and our important pieces come with their certificate. Have a doubt about a stone, or want to compare in person? Book an appointment at our Paris office — and discover our certified gems.
