Ruby in Zoisite, Mundarara Mine, Tanzania

These beautiful metamorphic rock specimens are composed of ruby in ziosite and pargasite, and are from the Mundarara Mine, Longido District, Arusha Region in northern Tanzania. This rock was discovered in 1949 in a location around 100km north-west of Mt. Kilimanjaro, and to this day the Longido District is the only source for such specimens. Rubies, a red variant of corundum, appear red due to trace amounts of chromium (Cr) replacing some of the mineral's aluminum. As a result of the chromium, ruby is UV reactive, causing it to fluoresce under ultraviolet light. In other words, it glows under black light, making this a bright addition to any UV collection. See an example of a similar specimen under blacklight in the photos. Approx. Weight & Dimensions: M0010 - 16.2oz. (459.26g) - 9.21 cm x 6.99 cm x 5.72 cm M0011 -  9.7oz. (274.99g) - 6.35 cm x 5.72 cm x 4.45 cm M0012 -  8.6oz. (243.81g) - 5.72 cm x 5.72 cm x 5.08 cm M0013 -  8.1oz. (229.63g) - 6.98 cm x 6.98 cm x 4.45 cm M0014 -  8.8oz. (249.48g) - 7.94 cm x 6.35 cm x 4.13 cm Mineral Information: - Ruby: Al₂O₃ (Aluminum Oxide, with trace Cr³⁺ giving the red color) - Zoisite: Ca₂Al₃(SiO₄)(Si₂O₷)O(OH) - Pargasite: NaCa₂(Mg₄Al)(Si₆Al₂)O₂₂(OH)₂ (Pargasitic Hornblende) Known As: - Anyolite (Unofficial) - Corundum-pargasite zoisite - Ruby in zoisite - Ruby-zoisite - Ruby zoisite - Tanganyika artstone