Glossary
Eye clean
Eye clean means that no inclusions are visible to the unaided eye at a normal viewing distance. Under a 10× loupe, features may well be visible. For coloured gemstones, «eye clean» is the most important clarity threshold for jewellery; in Type III stones such as emerald it is rare and correspondingly valuable.
Read more
- 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 2026-10-06