May 02, 2026 6 min readBuying Tips
A gemmological certificate is the single most important document in a sapphire purchase. Here is what it tells you and how to read it.
What a certificate confirms
A laboratory report typically confirms the stone is natural corundum (sapphire), records its measurements and weight, states treatment status, and — for some labs and stones — gives an origin indication.
- Identity — natural sapphire vs. synthetic or imitation
- Treatment — e.g. “no indication of heating” or “heated”
- Origin indication — where supported (e.g. Sri Lanka)
- Weight, dimensions and cut
Why it matters
Certification converts trust into evidence. It protects you against misrepresentation, clarifies exactly what you are buying, and makes the stone easier to insure and resell.
Reading a report before you buy
Check that the report is from a recognised laboratory, that the stone’s measurements match the gem in hand, and that treatment status is clearly stated. For premium stones, an unheated determination materially affects value.
