Rare Musgravite Crystal in Green Sapphire

Titapa Tanawansombat

A 6.59 ct faceted green stone, identified by standard gemological testing as sapphire, contained various inclusions such as needles, fingerprints, and a cluster of colorless and green crystals. The colorless crystals were identified as feldspar, and a transparent green prism-like crystal breaking the surface of the sapphire (see above) was confirmed as musgravite (magnesiotaaffeite) by Raman spectroscopy.

Musgravite, (MgFe,Zn)₂BeAl₆O₁₂, crystallizes in the trigonal system and is part of the taaffeite group. Musgravite is rarely found as an inclusion in corundum, making these crystals a unique observation for gemologists.