Tsavorite, a variety of grossular, forms in graphite-bearing metamorphic rocks- usually gneiss, which itself is embedded in limestone marble. The inclusions, which normally populate the inside of wavy fractures, consists of white angular fragments of calcite and grains of flakes of black graphite- minerals which the tsavorite incorporated from the encironment rocks. The inclusion scene is highly iagnostic, so that tsavorite can always be recognized, whether it is found in the Tsavo Park in Kenya, in the Tunduru area in Tanzania or at IIakaka on Madagascar. 


 source : Photoatlas of Inclusions in Gemstones