Glossary
Nigeria
In 2001 Nigeria became the first source of Paraíba tourmaline outside Brazil. The find sparked a long debate about whether the name «Paraíba» describes an origin or a type.
Paraíba tourmaline
In 2006 the laboratories agreed that «Paraíba» denotes a type of tourmaline: blue to green and coloured mainly by copper – regardless of country. The origin is stated separately in the report.
Sapphire
Together with Cameroon, Nigeria today supplies a large share of sapphires from basalt regions, mostly in darker blue, green and yellow tones.
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 2026-10-04