If you cannot find what you are looking for, get in touch and we will be glad to help.
Where a gemstone formed, and what has been done to it since, are among the most consequential questions in gemology. Answering them depends on comparing an unknown stone with well-documented reference samples.
No single test is conclusive. Opinions on origin and treatment draw on several independent lines of evidence that must agree.
X-ray fluorescence and related techniques measure minor and trace elements present at very low concentrations.
Comparing stones from different deposits and detecting diffusion-introduced elements.
Provides quantitative data that complement microscopic observation.
Absorption spectra reveal the causes of colour and features that change when a stone is heated.
Recognising heat treatment in corundum and identifying fillers in emerald.
Non-destructive, and sensitive to changes invisible under the microscope.
Results are compared with samples whose source and treatment history are reliably known.
Supporting conclusions on geographic origin and on natural versus laboratory-grown growth.
Anchors each conclusion to documented, verifiable material.
No. Some deposits produce stones with overlapping characteristics, and in those cases an origin cannot responsibly be stated.
Heating of ruby, sapphire and tanzanite and clarity enhancement of emerald are the most widespread. Diffusion, irradiation and fracture filling are also encountered.
Synthetic stones have growth features, inclusions and trace chemistry that differ from those formed in nature, and these can be detected with microscopy and spectroscopy.
Establishing species and variety through optical, physical and spectroscopic measurement.
Read More
Consistent description of colour, clarity, cut and weight under controlled conditions.
Read More
Locating and modelling internal features in rough and polished stones.
Read MoreAdvancing the understanding of gemstones through science, precision and innovation, from their formation deep within the Earth to the finished stone.
© 2026 Ann Gems Gemstone Research Institute. All rights reserved.
+1 937 803 2459
Make an Inquiry