Glossary
Treatment
A treatment is any process other than cutting and polishing that alters a gemstone’s colour, clarity or durability – for example heating, filling fissures with oil, resin or glass, diffusion, or HPHT and irradiation in diamonds. Reputable laboratories disclose every detectable treatment using standardised terms. At NOBILITH the laboratory’s statement appears in the dossier, including codes such as NTE or TE2.
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- KnowledgeHow to read a gemstone dossierA dossier brings together everything that describes a stone – from the laboratory report to custody. Here is how to read it in the right order.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
- GlossaryAbsorption spectrumWhen light passes through a gemstone, the stone absorbs certain wavelengths – the rest make up its colour.Read more
- GlossaryAfghanistanAfghanistan is an old source of ruby and emerald; both are mined in the mountains of the Hindu Kush.Read more
Updated 2026-10-04