Micro-World Gems & Gemology, Winter 2020, Vol. 56, No. 4

Blue Apatite in Pyrope-Spessartine Garnet

Pyrope-spessartine garnet with an unusual blue apatite inclusion.
Figure 1. This 5.33 ct red pyrope-spessartine garnet was faceted by the author to display the unusual blue apatite crystal within. Photo by Diego Sanchez.

The author recently had the opportunity to examine and facet a piece of garnet rough. The garnet, reportedly from Madagascar, was acquired from gem cutter and dealer Desmond Chan of Los Angeles. The rough was selected for the unusual blue apatite crystal nearly reaching the surface. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) chemical analysis indicated the rough to be a pyrope-spessartine variety. When orienting the stone in preparation for faceting, the author wanted the apatite inclusion to be the main focus of the gemstone. After slow and careful execution, a cut-cornered mixed-cut faceted gem was achieved, with the apatite eye-visible just under the table facet (figure 1). Oblique fiber-optic illumination was used to observe the world inside the gemstone, revealing a scene consisting of the blue euhedral apatite crystal paired with numerous iridescent intersecting needles of rutile (figure 2). This is one of the most unusual inclusions the author has seen in a garnet, and it is also notable as the gem was faceted to showcase the inclusion rather than hide or remove it.

Iridescent needles surround the blue apatite crystal.
Figure 2. A blue apatite crystal associated with intersecting iridescent needles was showcased. Photomicrograph by Jessa Rizzo; field of view 2.90 mm.

Jessa Rizzo is a staff gemologist at GIA in Carlsbad, California.