Tanzanite from Merelani Hills, Tanzania

Tanzanite, a gem-quality variety of the mineral zoisite, only occurs at one locality in the world- the Merelani Hills, in the shadow of 19,300 foot Mountain Kilimanjaro in the Arusha region of Tanzania. Since it's discovery in the 1960's, the Merelani Hills District has become famous in both the mineralogical and gemological worlds for it's incredible gem-quality crystals of species including tanzanite, 'tsavorite' garnet, chromian Diopside and Dravite, and more. Intense metamorphism (up to granulite facies) during the Proterozoic time period converted sedimentary rocks into high-grade gneiss, marble and dolomite, and intense folding associated with this event focused hydrothermal fluids into narrow channels and elongated pods known as 'boudins' (Wilson et al. 2009; Mineralogical Record Vol. 40 #5). This intense metamorphic event as well as the unusual chemistry of the precursor sediments led to the unique gem-bearing deposits mined today.  

Merlani Tanzanite mines with Mount Kilimanjaro in the background. (Photo copyright Richard Hughes, 2007)

Collector's Edge has been lucky to obtain some fine specimens from this prolific and important locality, ranging from inexpensive examples for new or frugal collectors, to superb specimens for the most discriminating collector. Please feel free to contact us at minerals@collectorsedge.com if you have any questions or would like to see a video of any specimens listed below. Thanks for looking and enjoy!