Geologically speaking, Colombian emeralds are the purest because the emerald deposits are the only ones on earth found in sedimentary host rock rather than in igneous rock. The primal mix of minerals that make up emeralds has not crystallized from direct volcanic activity as are African or Brazilian varieties.
Colombian beds are unique in that they are hydrothermal. The tectonic movements that created the Andes mountains forced the raw material of beryllium, chromium and vanadium in liquid and gaseous states into cracks in the already sedimentary medium and then cooled and crystallized with hydrothermal brine.
This saline solution washed out impurities such as iron that cloud other beryls. This unmatched process produced what some geologists consider to be the only “real” emeralds in the world.
The origin of Colombian Emeralds is very unusual since they are the only ones in the world associated with sedimentary rock, a fact that is evidenced by their excellent quality and has a direct impact on their high market value. Colombian emeralds are the biggest, brightest and the most varied in terms of color.
Colombia produces 70-90% of the world’s best emeralds and is featured in the Guinness Book of World Records with the largest emerald in the world at 7,025 carats.