Certification
Reading Gemstone Laboratory Reports
What a report certifies, what it deliberately does not, and the wording that separates a fact from an opinion.
6 min read
A laboratory report is a technical document, not a guarantee of value, and reading one accurately means knowing which of its statements are measurements and which are conclusions.
The three things a report addresses
- Identity
- What the material is, and whether it is natural or synthetic. This is a measurement and it is not in doubt. If a report says natural sapphire, it is natural sapphire.
- Treatment
- What has been done to the stone. Usually reliable, and phrased carefully — laboratories report the absence of heat as "no indications of thermal enhancement" rather than as a flat negative, because they are reporting what the evidence showed.
- Origin
- Where the material came from. This is a conclusion drawn by comparing the stone's inclusions and trace chemistry against reference collections. It is an expert opinion, laboratories say so, and two laboratories can legitimately differ.
Wording carries meaning
Colour descriptions such as "pigeon's blood" or "royal blue" are trade colour grades issued by specific laboratories against their own standards. They are not species classifications and they are not interchangeable between laboratories. A stone can carry the description from one lab and not qualify at another.
Where a report includes a comment or a note, read it. It is usually where the qualification lives.
When a report is worth commissioning
It is generally not worth it for calibrated melee or commercial parcels, where the report would cost more than the stones and would tell you nothing you did not already assume.
- Significant single stones, where the price reflects a specific claim
- Any stone sold as unheated, untreated, or from a named origin
- Anything represented as Paraíba-type or cobalt-blue spinel, where the premium over the ordinary version is very large
- Stones going into a piece where your customer will expect documentation
A note on affiliation
No dealer is endorsed by a laboratory. A supplier that can supply stones with GIA, GIT, GRS, SSEF, AGL or Gübelin reports is describing which documents accompany its stones — nothing more. Treat any implication of partnership or accreditation as a reason to look more carefully, not less.
Our own catalogue records a laboratory against a stone only when that stone physically carries that report.
Have a requirement?
Send the specification and we will come back with what matches.
