Laboratory reports
Treatment and enhancement
The treatment field in a report is often the one most relevant to value. How to read its wording – and why a missing statement proves nothing.
In a laboratory report, the treatment field records whether and how a stone has been altered beyond cutting. Because treatments strongly affect rarity and value, this field deserves particularly careful reading.
Typical wording
- "No indications of heating": the laboratory found no traces of heating. This is the usual wording for unheated corundum.
- "Indications of heating": the stone has been heated. Some laboratories add whether residues are present in fractures.
- Emerald: statements such as "none", "minor", "moderate" or "significant" describe the amount and effect of filling, often with the substance, such as oil or resin.
- "Beryllium diffusion", "lead-glass filling" or "coating": more far-reaching treatments with a considerable effect on value.
Certainty of the statement
Not every treatment can be detected with certainty. Some reports state explicitly that a treatment cannot be ruled out or that no statement is possible. This qualification is part of the statement and must not be omitted.
A missing statement is not a statement
If a report says nothing about treatment, this does not mean the stone is untreated. The question may not have been examined, or the type of report may not cover it. No stronger statement may be inferred from silence.
Stability
Some treatments are permanent, such as heating corundum. Others can change: fillings can dry out, leak or be damaged by heat and solvents. This affects care and resale.
Disclosure at the point of sale
International guidelines such as those of CIBJO require treatments to be disclosed at the point of sale. The seller must pass on the report's statements, not only the favourable ones.
In brief
The treatment field describes whether and how a stone has been altered, including qualifications. Read it in full and infer nothing from a missing statement. The treatment affects value, stability and care.
At NOBILITH
The dossier shows the treatment field in the laboratory's wording, including all qualifications. The care guidance on delivery follows this statement.
Sources
- LMHC: Information Sheets on standardised wording
- CIBJO: The Gemstone Book, section on treatments
Read more
- KnowledgeWhy a laboratory may say inconclusiveSometimes a question cannot be answered responsibly with the available data. What “inconclusive” means – and what it does not.Read more
- Gem LabGemmological microscopeThe most important instrument in the laboratory: under the microscope, inclusions, growth features and signs of treatment become visible.Read more
- Laboratory reportsUnderstanding a laboratory reportA laboratory report is a gemstone's most important document. Which information it contains, how to read it and what it does not say.Read more
- Laboratory reportsIdentificationIdentification is the first and most important statement in a report: which material is this? Why every word in it counts.Read more
Updated 2026-10-06