Different technical and analytical methods are basics in a good gemmological laboratory.
Each method is useful for a specific application:
Identification of natural gemstones and synthetics
Different way a natural or synthetic stone is growing
- Identification of physical treatments (e.g. radiation)
- Identification of chemical treatments (e.g. Pb-fillings)
- Analyzing the chemical composition and trace elements
- Identification of the geographical origin of a gemstone
ED-XRF (Energy Dispersive X-Ray Fluorescence) was developed in the 1980 and has become one of the most important
analytical methods. It is is used in many applications today (e.g. metals & alloys, minerals, glass, color pigments, plastics,
soil, food). The big advantage of the method is that no damage, X-radiation or even color change is caused on the sample.
ED-XRF is the only absolut non-destructive chemical analysis. Each atom is analyzed in the gemstone or mineral on incident
X-ray radiation. The resulting fluorescence signal is producing a complete spectrum of all the elements in a gemstone. From
Sodium (Na = atomic No 11) to Uranium (U = atomic No 92) all elements are precisely analyzed from 100% down to 0.0005%
with the new spectrometers from Skyray Instrument (China). Rough and polished gems can be precisely analyzed with ED-XRF
Three steps are important for excellent ED-XRF data:
The spectrometer is perfectly calibrated
The spectrum is the primary source of information
The analytical data is controlled by good standards
Separation of natural gemstones from synthetics.
Analyzing enhancement methods in a gemstone.
Analyzing the geographical origin of a gemstone.