Microworld Gems & Gemology, Summer 2015, Vol. 51, No. 2

Unusual Pink Sapphire Bead

Pink sapphire bead with drill holes.
Figure 1. This 17.25-mm-long bead contained more than 30 randomly oriented drill holes. Photo by Nathan Renfro.
How to ruin a gem-quality natural untreated tumble-polished sapphire? Fill it with numerous drill holes! At 9.36 ct and measuring 17.25 × 9.13 × 6.21 mm, the purplish pink bead shown in figure 1 had the perfect form to produce a very attractive faceted pear-shaped gem, but that effort seemingly ended in failure. These drill holes, more than 30 of them in all, stood out in high relief because they were at least partially filled with a dark unidentified residue. This leaves the question of why anyone would drill so many holes in a perfectly good sapphire. Closer microscopic examination revealed a possible clue. At the surface of three of the holes were small bright red fragments, identified by Raman analysis as ruby (figure 2). Yet we were unable to determine if the fragments were natural or synthetic, due to their small size. Further analysis with advanced analytical equipment would be required to make this separation. The implication is that if all the drill holes contained a bright red ruby, this would have enhanced the light pink appearance of the bead. Because so many of the ruby fragments were missing, the unsightly drill holes made for a rather unattractive gem bead.

Ruby is visible in the drill holes using diffuse transmitted light and oblique fiber-optic illumination.
Figure 2. Three of the drill holes, seen here using diffuse transmitted light and oblique fiber-optic illumination, contained a small ruby fragment identified by Raman analysis. Field of view 4.40 mm. Photomicrograph by Nathan Renfro.

Nathan Renfro is the analytical manager of the gem identification department, and analytical microscopist in the inclusion research department, at GIA in Carlsbad, California. John I. Koivula is the analytical microscopist at GIA, also in Carlsbad, California.