Micro-World Gems & Gemology, Spring 2019, Vol. 55, No. 1

“Double Bubble” Multiphase Inclusion in Beryl

Large rough beryl crystal containing multiphase inclusions.
Figure 1. A 64.10 ct pale green rough beryl crystal containing noteworthy multiphase inclusions. Photo by Robison McMurtry.

Beryl often hosts multiphase inclusions consisting of all possible combinations of solid, liquid, or gas inclusions. These remnants of the growth environment become trapped within negative crystals during formation. The fluid is trapped as a homogenous liquid that separates into component phases during cooling. Jagged three-phase inclusions commonly found in Colombian emeralds are perhaps the most well-known multiphase inclusions in beryl.

Gas within gas at room temperature (left), after exposure to the microscope well light for 45 seconds (center), and after one minute (right).
Figure 2. Photo series of a prismatic multiphase inclusion displaying a “double bubble” of gas within gas at room temperature (left). The smaller bubble shrinks by about half after approximately 45 seconds of exposure to the microscope well light (center) and completely homogenizes after about a minute (right). Photomicrographs by Hollie McBride; field of view 2.34 mm.

A 64.10 ct pale green rough beryl submitted by L. Allen Brown (All That Glitters, Methuen, Massachusetts) contained a plethora of prismatic three-phase negative crystals with a notable suite of gas bubbles, several species of extremely small daughter crystals, and an aqueous solution (figure 1). At room temperature, the gas phases were out of equilibrium with each other, which gave rise to a “double bubble” nested appearance: a gas bubble within a second, larger gas bubble. Over the course of about a minute, the gentle heat of the microscope well light warmed the smaller gas bubble enough to completely homogenize with the larger bubble so that only one bubble remained (figure 2).

Hollie McBride is a staff gemologist at GIA in Carlsbad, California.