Zoisite (Var: Tanzanite)
Small Cabinet, 7.2 x 3.2 x 2.3 cm
Merelani Hills (Mererani), Lelatema Mts, Arusha Region, Tanzania
This is an unusually fine specimen in several regards. Firstly, it has superb color - probably the prime attribute you first look for in a world-class tanzanite. All three colors of a natural trichroic tanzanite crystal are represented in strength: violet purple, blue, and a rich magenta-red along the c-axis. In the best tanzanites, to my opinion, some of the red from the c-axis (long axis) transmission of light bleeds over and is seen in horizontal planes, from one side or another, as in this case. Many larger tanzanites are too big or too opaque for the red color to transmit through the whole specimen when the piece is lit by a light aligned from the top or bottom: not so with this piece, where the deep red color not only shines out the top when lit from below, but does spill over a bit and mix with the purple hue form the sides. Secondly, it has top glassy luster and internal brightness both (many larger tanzanites lack one or another feature). Lastly, this piece has excellent geometry. The mine produces singles in abundance, and few clusters, with a different look to them. This piece is a rare, natural doublet cluster, with great symmetry. The twin peaks of the piece are both very gemmy. Cushioned between them, in the crevasse, is a small prehnite ball for accent. This specimen is illustrated with a small and elite group of well-known, important specimens from the mine in the central photo folio of the recent special journal/book dedicated to Merelani's riches, MINERALOGICAL RECORD, Nov-Dec 2009. Weighs 113 grams.