Fluorite in Brazilian Alexandrite
An octahedral fluorite crystal in a 1.25 ct Brazilian alexandrite. Photomicrograph by Hikaru Sato; field of view 2.37 mm.
The author recently examined a 1.25 ct transparent oval modified brilliant alexandrite. The stone possessed a single crystal inclusion in the shape of a perfect octahedron (see above). Raman analysis identified the crystal as fluorite (CaF2), which supported the alexandrite host’s origin determination of Brazil.
Fluorite crystals are occasionally found in Brazilian alexandrite (Z. Sun et al., “Geographic origin determination of alexandrite,” Winter 2019 G&G, pp. 660–681). However, they are often rounded in shape and rarely perfectly octahedral like the observed crystal here.
