Merelani Mines, Arusha, Tanzania
This is a large tanzanite crystal, remarkable in that it is both a rare cluster and that it is unrepaired. The Merelani Mines are still the only source in the world for gem tanzanite specimens and gem rough. Weighing 154.3 grams (771.5 carats), few large tanzanites of this size have been found. All terminations are intact and lustrous on the display faces. The luster is far beyond the "average"—it is like polished glass: vitreous, bright and sparkling. The intensity and color saturation of the crystal (enhanced by simple heating of the crystals at the mines) is apparent from a distance. The crystals are the top blue color in one axis, and when rotated 90 degrees, show a top purple color from another axis. This dichroic effect, a classic feature of tanzanite, is visible even under simple incandescent lighting. From certain angles of display, the piece is so thick and intense that light refracts and both purple and blue can be seen at the same time – a rare phenomenon. Although not as transparent as some specimens, this is one of the few larger specimens at a reasonable price we have seen that conveys the visual "impact" of a great tanzanite without a six-figure price tag. Mined in 2009, this crystal cluster is suitable for any museum or private collection.
Weight: 154.3 grams (771.5 carats). Measures 5 3/4 x 1 3/4 x 1 1/2in