Vietnamese Skyline

by Wimon Manorotkul

Hogbomite-filled dislocations in a Vietnamese spinel.

vietnamese skylineHogbomite-filled dislocations in a Vietnamese spinel. Photo by Wimon Manorotkul; vertical field of view 4 mm.

In the red spinel from Vietnam’s Luc Yen district in the figure above, layers of iridescent needles stretch skyward like a futuristic horizon from a science fiction novel. Such hogbomite-filled dislocations are a common sight in red, pink, and blue spinel from Vietnam. According to Gübelin and Koivula (Photoatlas of Inclusions in Gemstones, Volume 2, Opinio Verlag, Basel, Switzerland, 2005), hogbomite (Mg,Fe)2(Al,Ti)5O10 is found in spinel via isomorphous replacement.

About the Author

Wimon Manorotkul has been involved with gems and gemology since 1979, as a lab gemologist, instructor and photographer. She is an Accredited Gemologist from Bangkok's Asian Institute of Gemological Sciences and for many years directed their lab. Wimon also qualified as a Fellow (with honors) of the Gemmological Association of Great Britain. A skilled gem photographer, her images have been featured in books and magazines around the world, particularly Ruby & Sapphire: A Collector's Guide, Ruby & Sapphire: A Gemologist's Guide and Inside Out. Wimon not only photographs gems, jewelry and mineral specimens, but is also an expert photomicrographer. In 2013, she founded Lotus Gemology with her husband, Richard Hughes, and daughter, E. Billie Hughes.


This article first appeared in Gems & Gemology, Spring 2022, Vol. 58, No.1, p. 69.

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