GFCO GEM LAB® has gathered data and samples for purpose of origin determination for the following countries & mines:


Based on these samples and the experience gathered through the testing of thousands of items, the laboratory bases its conclusion on:

  • the specific inclusions using microscope observation;
  • the structure of the color banding;
  • the fluorescence to LW and SW;
  • the presence of chromium, cobalt and iron;
  • the refractive index;
  • the colour

The laboratory offers origin determination whenever possible when reaching a sufficient degree of confidence. Origin are available for rubies, sapphires, emeralds, spinels, opals, jadeite and demantoids. Gemstones from different mines and world locations may to some extent have overlapping characteristics and new mines with similar characteristics may appear at any time. Thus, an origin opinion does not represent a guarantee of origin but what is deemed a reasonable probability of such origin by the gemologist(s) at the time it is given based on the samples, theoretical knowledge and practical experience.