Auction Win: Tanzanite .44ct

Locality: Merelani Hills, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania

Valued ~$60-100. Tanzanite is a blue to blue-violet gem variety of the mineral zoisite, with the chemical formula Ca2Al3(Si2O7)(SiO4)O(OH), and its color comes from trace vanadium. It was first discovered in the Merelani Hills of Tanzania in 1967 and named after the country where it is exclusively found. Tanzanite is uniquely trichroic, displaying blue, purple, and yellowish-green colors depending on the viewing angle.

Merelani Hills, located on the slopes of the Lelatema Mountains in Tanzania's Simanjiro District, is the world's only source of the rare gemstone tanzanite, first discovered here in 1968. This 2 km wide by 50 km long mining area is subdivided into four major blocks (A, B, C, D) and is geologically renowned for gem-quality tanzanite and grossular occurring in boudinaged pegmatitic veins and hydrothermal fracture fillings. Beyond tanzanite, the locality is a premier destination for collectors seeking exceptional tremolite crystals, which were discovered in 2005 and are considered among the world's finest occurrences. Today, the site remains critically relevant to collectors as Block C continues high-tech production of 1.5 to 2 million carats annually, while Blocks B and D support artisanal mining.