Micro-World Gems & Gemology, Spring 2022, Vol. 58, No. 1

Vietnamese Skyline

Wimon Manorotkul

Iridescent needles in a Vietnamese red spinel resemble a skyline.

Hogbomite-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 skyline 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 is a gemologist and co-founder of Lotus Gemology in Bangkok.

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