Ancient Tourmaline and Beryl from Afghanistan
The two most interesting pieces, a pink bird (above) and a very pale blue bead (below), were studied in detail. The bird had a light green bottom section, measured 13.9 × 13.6 × 7.6 mm, and weighed 9.52 ct, with a refractive index close to 1.63. It was strongly pleochroic (pink and colorless), and it was uniaxial negative in a conoscope. In both short- and long-wave UV light the center was inert, but a thin triangular zone of light blue fluorescence was visible near the surface. These tests confirmed the stone’s identification as tourmaline. It was originally a “watermelon” tourmaline, pink with a green rim, but only a small part of the green rim had been preserved.
The pale blue bead was set in a heavily corroded metal, probably bronze. The entire piece measured 20.7 × 12.3 × 6.7 mm and weighed 20.28 ct, with an RI close to 1.59. The stone was weakly pleochroic (very light blue and colorless), inert in UV light, and uniaxial negative in a conoscope. These results indicated a very pale aquamarine. The identification of both beads was confirmed by their Raman patterns, collected by A. Gilg (Technical University of Munich).
Both beads are possibly among the oldest of their kind. Large and historically significant rubellites have been reported from the 14th and 16th centuries, and a single beryl bead from Nubia has been dated back to Predynastic time (before 3200 BC), but few details are known. The first beryl locality of significance was reportedly the Egyptian emerald deposit exploited as early as the Ptolemaic era (after 332 BC).
Both tourmaline and aquamarine are typical pegmatite minerals. Gem-bearing pegmatites have been mined since the 1970s in the Nuristan province of eastern Afghanistan and northern Pakistan—the possible origin of both beads.