gems, spinel, Vietnam, Luc Yen, inclusions

Lotus Gemology received a vivid cobalt blue spinel from Vietnam for laboratory testing. Despite its small size of well under a carat, its stunning color stood out immediately. The stone proved to be exceptionally clean. Most cobalt spinels we test contain fissures, small crystals, or other inclusions. After careful examination, we found just one tiny inclusion, a transparent teardrop-shaped crystal. Raman microscopy revealed the crystal to be actinolite, a mineral in the amphibole group. As far as we are aware, this is the first reported inclusion of actinolite in spinel.