Tanzanite on Prehnite and Graphite
Merelani Mines, Arusha, Tanzania
Small Cabinet, 6.8 x 5.2 x 3.4 cm

A stunning and unusual specimen featuring a 5 x 3 x 1 cm trichroic tanzanite crystal sitting starkly in matrix of calcite, green prehnite, and graphite. The crystal has a natural rich blue color, unheated by man to emphasize the blue saturation as they do in the gem trade. Note the red/violet color showing up the C axis, as the piece is lit from the bottom. Few matrix tanzanites have ever been recovered, at a guess only at a ratio of probably 1:1000 to the single crystals despite the productivity of this mine. Part of the reason is the geology, and part of the reason is that it was always easier for miners to chip the crystals out for the gem trade instead of to try to collect them as specimens with attached matrix for our world. Specimens like this were therefore always prized in the mineral world, because they display so nicely and show the environment in which the tanzanite forms. Even among matrix specimens, though, there were only 2 pockets that I know of with such amazing association as we see here, to the green prehnite. This came out in 2010. It has been in a private collection since that time. This special piece is complete 360 degrees, all around, and features a fully exposed tanzanite crystal sitting as perfectly as you could ask for. Comes with a custom lucite base.