https://www.gia.edu/CN/gems-gemology/summer-2018-gemological-characterization-of-sapphires-from-yogo-gulch-montana
Gemological Characterization of Sapphires from Yogo Gulch, Montana
A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.
yogo gulchgemologicalcharacterizationsapphiresmontana