corundum, Burma.12, gems, Mong Hsu

A newly discovered ruby occurrence approximately 10 km north of the intensively worked Mong Hsu deposit in Myanmar is described as a possible extension of that field. The unnamed locality lies about two and a half hours’ walking distance from Mong Hsu along mountain ranges. Preliminary information derives from specimens collected in mid-December 1994 by a gemmology student from Taunggyi University, together with subsequent reports from the area. A bulk sample weighing 570 carats contained ruby and several associated minerals. Tourmaline accounted for approximately 10% of the sample, while quartz, pyrite, tremolite and bismutite were also recorded. Reports of pegmatite veins dipping westwards at approximately 25–30° contrast with the eastward dips of 20–25° cited for Mong Hsu. The note records this structural difference without establishing the geological relationship between the two occurrences. Two promising ruby specimens were fashioned into cabochons and produced attractive stones of better quality than initially anticipated. No characteristic inclusions had been recognised in the specimens examined at the time of reporting. Most ruby crystals were broken and sharp-edged, ranging from flesh red to brick red and from translucent to nearly opaque. Their surfaces displayed pits and etched lines filled with iron oxides. Dark cores resembling those familiar in Mong Hsu ruby were observed, providing one point of comparison with the established deposit. The sample also included complete, dark, lustrous prismatic crystals. Accessory crystals occurred on ruby prism faces, predominantly oriented parallel to those faces, although some projected outwards. Green tourmaline was recovered as an additional component of the assemblage, with the largest reported piece weighing three carats. As of April 1995, an exploratory party from the government Department of Geological Survey and Mineral Exploration was investigating the locality to assess its potential as a future ruby resource. The account presents an early description of the material’s appearance, associated minerals and reported structures, while leaving the proposed extension and its commercial significance subject to further exploration.