Micro-World Gems & Gemology, Summer 2022, Vol. 58, No. 2

Fracture-Filled Emerald with Mysterious Filler Patterns


The fracture filling material displayed a visually interesting pattern in this emerald.
Emerald filler with labyrinth- and convolution-like pattern. Photomicrographs by Ungkhana Atikarnsakul; fields of view 2.0 mm (left) and 2.7 mm (right).

Emeralds are known to have natural cracks or fractures. The filling of surface-reaching fractures with various oils and resins is the most common practice to minimize fractures to improve an emerald’s appearance. The author recently examined a 3.04 ct emerald that revealed a mysterious filler pattern along the fractures, resembling a labyrinth and convolution (see above). Fracture filling can be identified using various methods. In this case, it displayed a chalky fluorescence under long-wave ultraviolet flashlight and was also detected with simple microscopic observation and fiber-optic lighting. The internal graining, irregular two-phase inclusions, and long needles within this stone indicated a natural origin. This was a unique and visually interesting pattern in the fracture filling material of an emerald.

Ungkhana Atikarnsakul is a staff gemologist at GIA in Bangkok.