Gem News International More of the Interesting and Unusual – Tucson 2014 Duncan Pay April 30, 2014 Figure 1. This emerald crystal, reportedly from Muzo, Colombia, is approximately 35 mm long and contains an eye-visible multi-phase inclusion. The gas bubble within the inclusion moves a few millimeters as the crystal is tilted. Photo by Duncan Pay, courtesy of William Johnson, Natural Formations. About the Author Duncan Pay is editor-in-chief of Gems & Gemology.