Since ancient times, the Badakhshan Province in northeastern Afghanistan has been known for its gem deposits, most prominently the lapis lazuli mines near Sar-e Sang in the Kokcha valley.and cabochons, but in rare cases also as transparent faceted stones.

Gem-quality spinel (MgAl2O4) from Tanzania is well known in the trade for many decades. Most of these spinels are purple or pink to saturated red. Especially famous are pinkish red spinels from Mahenge, which in fact are found at the locality Epanko (or Ipanko), about 7 km south of the small township of Mahenge

The spinels were nearly free of any inclusions except for a few tiny colourless forsterite inclusions. In combination with trace element analyses, the origin of these spinels could be unambiguously attributed to the famous spinel mines near Kuh-i-Lal, located in the Pamir mountains in southern Tajikistan, close

Radiometric U-Pb dating is a promising tool in gemstone testing and is used at SSEF as an advanced analytical procedure since several years. However, this method is usually only applicable when the gemstone presents sufficient traces of radiogenic elements either in its crystal structure or within a solid inclu