specimen
Details
ColorsBlack
Origin
Mwajanga, Simanjiro District, Manyara Region, Tanzania
SizeMedium
Dimensions2.1 x 8.0 x 1.7 cm
Species
Description
The Tourmaline locality at Mwajanga in north-eastern Tanzania reportedly only contains the species Dravite from the Tourmaline group, although this occurs in a bewildering range of colours and crystal habits. This rather splendid and elegant crystal, some 8 cm tall, is more than it first appears to be. The opaque, intensely dark leafy-emerald green crystal appears jet black, even when back lit and on examination of the termination pinacoid surface, all evidence points to this being a twinned pair of crystals, but of such exact match and symmetry, are perceived as one single prism. The pinacoidal face shows clears re-entrant angles in perfect symmetric alignment across the prism. Although subtle, a vertical plane of symmetry can be seen down one prism face, which meets the re-entrant axis. The species of Tourmaline is not specified but is most likely Dravite in accordance with the known mineralogy of this deposit.