Dumortierite + Sapphirine

Madagascar + Tanzania are well-known for a number of uncommon + rare minerals, but lately we are seeing more uncommon gem materials from Tunduru, Tanzania; Dumortierite, when transparent, is violetish gray/brownish pink + they are usually found in mine-run parcels (mixed lots); Sapphirine, when transparent, is gray/violet/red + they are commonly found in mine-run parcels (mixed lots) + both Dumortierite and Sapphirine, if found in alluvial sources look like water-worn pebbles and are often confused with mainstream colored stones + standard gemological tests may identify both specimens, if you have master-stone specimens for quick comparison, but if doubtful always consult a reputed gem testing laboratory.