Glossary
Absorption spectrum
When light passes through a gemstone, the stone absorbs certain wavelengths – the rest make up its colour. In a spectroscope the absorbed regions appear as dark lines or bands. This pattern works like a fingerprint: it reveals which elements create the colour and helps laboratories identify stones and narrow down treatments or origin.
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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
- GlossaryAfghanistanAfghanistan is an old source of ruby and emerald; both are mined in the mountains of the Hindu Kush.Read more
- GlossaryAsterismAsterism is the star effect of certain gemstones: on a domed stone a four- or six-rayed star appears and glides across the surface as the stone moves.Read more
Updated 2026-10-06