Gemology Hub | Gemstone & Mineral Identification Guides

EDXRF stands for energy-dispersive X-ray fluorescence. It is a laboratory method for examining chemical elements in a gem without drilling a sampling hole. The long name describes a useful principle: elements emit characteristic X-rays when excited. How the measurement works An instrument exposes the sample to X-rays and measures the energies of the X-rays emitted in response. Peaks in the resulting spectrum help identify elements. With suitable calibration, the measurements can also provide information about their amounts. SSEF’s 2011 article explains why this approach is useful for both loose and mounted gems. The article describes the introduction of a particular instrument at that time; it is not a statement about the laboratory’s entire current equipment. What chemistry can help explain Chemical data can support gem identification, colour research and some geographic-origin investigations. It becomes more informative when combined with knowledge of the material and reliable...

A gemstone’s colour depends partly on which wavelengths of light it absorbs and which remain available to reach our eyes. UV-Vis spectroscopy measures this interaction. It turns a colour observation into a pattern that a gemologist can study and compare. What is an absorption spectrum? An absorption spectrum shows how strongly a material absorbs light at different wavelengths. Peaks and bands can provide information about colour-producing elements or other features inside a crystal. Some useful information lies outside the light we can see. SSEF’s 2008 article explains a portable instrument developed for testing away from the main laboratory. It discusses applications to colour research and supporting evidence for sapphire origin analysis. The historical equipment specifications should not be assumed to describe all instruments used today. Why orientation can matter The spectrum must be measured and interpreted under suitable conditions. The observed colour and absorption behavi...